Indeed the Ultramorph is just a term to describe the ultimate version of a infection, and Alien Engineers its a bit vague but it could be it was infected by the same Face Hugger type that infected Shaw and the other Two Crew.. (Ravel and Chance)
The concept work that seemed to differ them a bit, but have to bare in mind for most things in those works.. they had more than One Concept.
So when we talk about the Ultramorph it depends which one as the concept art had many kinds, the same was with the Deacon which is a Ultra-morph too so to speak (Birth from a Engineer) it also had a few different designs... but as we saw One on Film we know what its intended to look like.
I think the Deacon is interesting to see how it develops, i have covered it a number of times to how Logically it would develop and potentially procreate.
The Neomorph its hard to tell, as we have yet to see it up close, we have leaked prop work but we cant guarantee if those designs would be 100% accurate to the final product.
I would however assume, it would have Xeno traits and carry over Acid Blood and Two Sets of Jaws... but they could change these things... and maybe if they do, then maybe there would be a good explanation for it.
i.e how it came to be.. i.e if its not a direct result of the Black Goo, but something experimented on over and over that leads to the Spores... so some Xeno traits are lost.