Could the Last Engineer have been a synthetic?

K-Theory said,"If humans and "Engineers" are 99% the same genetically, would we not progress the same technologically? "

I agree with this at first glance, yet I think I can explain why not.

From my past knowledge, I think most historians theorize the invention of fire as being started by lightening.  This eventually would be obtained and kept burning by some species.  I believe fire is considered to be one of the most useful technologies to mankind since it shaped the way we eat, what we eat, where we could live, how we fight, how we see, how we relax, how we communicate, etc.

I think it is believed that fire was a random technological invention to mankind that mankind eventually learned to use which led to a whole new way of living.

Now, let's say we have two similar species living on different planets.  The one that receives fire first is the one that should, technically, become more dominant and eventually invent more things from fire.  Maybe the Engineers just received fire first and were allowed to grow sooner.

Plus, the Engineers could have evolved into humanoids 1 million years before creatures came out of the oceans.  Maybe the Engineer planet was more acceptable for life before Earth?

With your point regarding if Engineers are synthetic... Sure, it could be possible.  Or maybe they're half humanoid, half synthetic.  We really don't know much about the Engineers, so it is hard to say what they are.  Maybe they come from another dimension?  If that's the case, we could really be lost in understanding them.

Hello K-Theory
A nice topic to think about, congratulations.
the idea of a synthetic biomechanical engineer is a fascinating idea, there is too much perfection in being seen in prometheus unlike civilians on paradise seen in AC.
my thinking about this, however, is a little different, I think the engineers of LV-223 are soldiers who have taken on some kind of concoction similar to the black go, which instead of mutating them has improved, the comparison between the worm and the snake mutated of prometheus, we remember a fundamental ingredient of the biomechanical suit, fused with the body.
the synthetic idea should be deepened because the engineers on LV-223 died from the contamination of the Black go Virus unlike David who even touches it with the index.

"Au Revoir Shoshanna"

I actually feel this is Pretty much what we could be shown....

Ridley Scott is Fascinated with AI and he said the next movie would be about AI and people thought, ok so its another DAVID movie only much more about him....  But RS mentioned that Batty and Racheal were AI

AI DOES NOT = Machine...

AI simply refers to a Artificially (not Naturally Occurring/Created)  Life-forms, (or also Intelligence) this does not have to be just Synthetics.... and so ENGINEERING a Embryo to modify its Genomes in a Attempt to make the Perfect Human Specimen Grown in  a LAB would contribute to being a AI

The ELDER Scene in Prometheus was removed, because RS did not want to MEET God in the first movie, so this means the LV-223 Engineers and Sacrificial Engineers were not GOD's they must therefore had served a Hierarchy or been a Sub-Creation to some other Race.

RS said David and Dr Shaw would meet some beings on Paradise, who are not GOD's in the Traditional Sense.   When we get to Alien Covenant the Engineers her look DIFFERENT the Hall of Heads look like the Elders from Prometheus, RS says they are the Apostles, Wise Men and Superior beings but to whom?

RS then makes a Fascinating Claim..  those Planet 4 Engineers are the ORIGINALS now this is interesting, and while Prometheus we had the ELDERS we need to remember this scene is NOT part of the Movie and so we maybe cant ACCEPT this is how the Elders Look.... 

Thus... the Elders could look similar but not have the Pale/Marble like Skin and Dark Eyes of the Prometheus Engineers, they could instead be Older Frail looking versions of the PLANET 4 Engineers.

Prometheus we only saw a Lone Pale Engineer, and then more of the same in those Bio-Mechanical Suits...  if THESE guys are not the Originals.

Then it stands to Reason they could be Genetically Modified Engineers/Creations...  Thus in effect they could be to the PLANET 4 Engineers as REPLICANTS are to Mankind.

Maybe there was a Rebellion, and these Organic Engineered Engineers, then started to experiment and Evolve themselves so that they incorporated the Bio-Mechanics with themselves?

There is so many ways the Differences could be explored, but i do think that the Prometheus Engineers could be those Planet 4 Engineers versions of DAVID only just Biological.

The Source i had from Feb 2015 did say that those Engineers had more in common with DAVID than us. But they also said the Engineer Race is connected Genetically to Mankind and that Current Mankind are the 4th/5th Generation of Mankind, and Biblical Events had happened but not to our Generation, and also implied that Paradise was kind of literal to the Biblical Account, but NOT on Earth as the Biblical Account.

This all seems to make sense to what AC had shown us.

I am left wondering out of all this, as to whether David creates Engineers. If a species of humanoid discovered fire well in advance before another then maybe it makes sense that the technology that then evolves would hit some problems along the way. The species that discovers fire later on, I think would also make similar mistakes along the way with its technology and so history repeats itself. But what if one species becomes so advanced that it creates an AI (manufactures life) that seeks to destroy it. If having rectified the problem, by whatever means , that species then discovers another species that is evolving along the same path and sees that it too is going to evolve its technology to create an AI, then there is a choice to be made. Do you let that species evolve and see what happens or do you destroy it, before it creates an AI that can destroy both species?

We know David has worked out how to create a xenomorph, something that according to the mural in Prometheus, the Engineers already have prior knowledge of. In order to gain that knowledge David wiped out the Engineers on Planet 4, but what if the Engineers knew that if humans ever developed technology to a certain level that the outcome could be David, and so wanted to destroy humans 2000 years ago to prevent human technology evolving. They basically did not want humans repeating their mistakes.

Given that David now has a ship full of colonists at his disposal, could it be possible that he might want to evolve his experiments into creating something that the Engineers fear could be highly destructive, and part of this may be creating Engineers from the human colonists. Perhaps the Engineers as we currently know them try to put an end to Davids work, but a juggernaut full of eggs makes for an escape and end up crashing on some planetoid/moon somewhere ( not LV426). Just to complicate things a little further, but what if something like this has all happened before, only last time a ship ended up crashing on LV426.

"The species that discovers fire later on, I think would also make similar mistakes along the way with its technology and so history repeats itself"

Reading the whole of your post, i think some elements certainly are possible, we could be seeing  a re-occurring theme.  Certainly at the broad strokes this seems it could be the case.... as we are shown a Tale of Creation, Sub-Creation, Rebellion and Repeat.

It could play out as you mentioned Batchpool and the Engineers had seen something like this prior and wanted to intervene with Humanity to Prevent it happening again...  The whole options are varied but i think a pattern is their broadly.

The LV-223 Engineers could be the DAVID of the Planet 4 Engineers, why who knows if the LV-223 Outbreak was caused by Planet 4 Engineers wishing to Sabotage and Eradicate those LV-223 Engineers?

I am not so sure on this, because it kind of contradicts how i view the Planet 4 Engineers as far as how they would Welcome the Juggernaught if they know about LV-223 the Black Goo and Experiments and more so a Sub-Creation/Evolved Group of Rogue Engineers...  But then a part of me can surely see these Engineers in Prometheus as ones who have Evolved themselves to that level.

Maybe the Hubris of doing so came at a cost, and so the Planet 4 Engineers turned their backs on the Genetic Experiments/Evolution attempts due to the Problems encountered in the past....  this seems plausible.. but again kind of conflicts with how they would welcome a ship that would be connected to a Past that had known to be  a great Hubris for their kind... even if they are not aware of the Xenomorph/Black Goo Variety.... but i think if they lacked knowledge of this,  and the LV-223 Engineers were a Project and Faction of beings who Evolved themselves to incorporate the Bio-Mechanical Atheistic, would this not be a positive trait?   But then why not JOIN this Evolutionary Path?   Why Shun it?

If they knew of the Hubris in maybe messing about with Bio-Mechanical Enhancements leads to some Mutations that lead to something like what they experimented on LV-223 with.... would those Planet 4 Engineers not be weary of the incoming ship?

Maybe the Bio-Mechanical Engineers are Engineered like this as Super Soldiers, so maybe they are in effect the Engineers versions of Clone Troopers, or Universal Soldiers where they are created for certain tasks.... but what are these tasks, and if the Planet 4 Engineer are aware of this purpose, if it in anyway links to Black Goo as far as anything related to Xenomorph Organisms... then again why would those Planet 4 Engineers seem so welcoming and have no concerns for the Danger.

So there is a lot to ponder really...

Unless the Bio-Mechanical Aesthetic/suits is something they are aware of and these beings maybe had to Genetically Alter themselves to be like the LV-223 Engineers but these Enchantments started to produce negative effects as far as the impact Mentally on those beings.   So they turned there backs on this Technology...

But then again this Technology to a degree is still evident on Planet 4, but we dont know if those Planet 4 Engineers could just as easily use those Ships and suits without actually having to be Bio-Engineered like the LV-223 Engineers...  If David and Dr Shaw could travel with one of their ships.... then there is no Reason why the Planet 4 Engineers could not use them too..

So you dont have to be a Bio-Mechanical Suited LV-223 Engineer to use the Technology... maybe?

I think in the broad sense...

It is indeed showing us that a Hubris to those Planet 4 Engineers is to stay and live simple lives like they are shown....

*Do-Not: try and Genetically Evolve oneself, and incorporate Genetic Enhancements or Bio-Mechanics.

*Do-Not: attempt to Sub-create other Intelligent Life-forms.

*Do-Not: attempt to teach other encountered or created Life-forms all the knowledge and secrets of your race (or even severely limit this knowledge).

We can see these Rules should have been applied to Mankind from our point of view, because if we attempt any of these and are successful then indeed you could face a similar scenario to what may have faced the Engineers.

*Creating a Synthetic in David who is superior to us in almost every way, that has Free-will and Emotions certainly could lead to a Rebellion to replace Mankind as we have seen explored in many a movie from Terminator, Matrix and I-Robot and others.

*Genetically Creating Super-Humans or Genetically Enhanced versions with little or no flaws, could lead to these beings determining they are more superior to regular Humans and then even see that there is no need for our Original Species.

Both TWO very possible Future Scenarios if we Evolve Genetics and Science to far without any bearing on the implications.

We even see a similar theme in Biblical Creation (other Creation Mythos too)....   Where in Hubris to GOD, creating Lucifer as Perfect and allowing him maybe that little more Free-Will (David) than the other Angels (Walter) proved to be a massive mistake by GOD.  You can surely see a connecting theme with David and Lucifer 

Ridley Scott had referred to the Engineers as Fallen Angels, he also hinted they are not GODS.... so with the Planet 4 Original Engineers comment it can get us to start to ponder if the Fallen Angels Moniker applies... if it applies to all Engineers or NOW just those Prometheus looking ones..

I think we also see the Engineers are/were very Naive  and Arrogant... if we look at Prometheus that is.... we can see its almost like when they decided to abandon us, they surely must have felt that without their help in Evolving us Genetically, Technologically and Culturally we would have been no more than CAVE-MEN so i feel another Hubris of their Species was to ASSUME without their interaction, that Mankind WOULD-NEVER evolve past the Level of Technology that we was at Thousands of Years ago by OURSELVES

This i feel is ONE reason why the Engineer in Prometheus kind of looked on to David with some Pity and Curiosity...   But the other reason for this reaction could also be INDEED that the Engineer was to his Hierarchy/Creators as David is to us.  I am kind of more inclined to this kind of thinking...

So the Engineer had to destroy David, because he realizes the Threat that him, and indeed Mankind Posses to HIM (Engineer) or indeed all Engineers, especially if this Engineer knows that his kind/faction had rebelled against the Original Engineers etc.

I do feel if RS is going to show us 3-4 Players incoming in the next movie... then the 3rd/4th Players i feel must be similar... so its either like TWO Human Factions... one maybe having NO knowledge of what to expect, the other with Full Knowledge of what to expect.

But then that 3rd/4th Party could also be our LV-223 Type Engineers and Planet 4 type.