The concept work does give a number of clues...
As far as the Derelict... who knows, i think they either recover the Derelict or they get there hands on another Engineer Ship... we have to remember the movie is set 20+ years after Aliens and 100 years after Covenant give or take .
The Questions then have to be asked... would the company wait 20 years to go and recover the Derelict? or had they recovered it a lot earlier and simply the S£"%" dont hit the fan until after a considerable time of them having it in their possession?
Also Ripley manages to somehow come across something related to Engineer Tech.... is this something they come across or is it reverse Engineered from the Engineer Tech or Derelict?
We also have to wonder what does Ripley do for 20 years and then what makes her come back into the Franchise... my money would be that she finds out the Company has its hands on a Derelict/Juggernaut ship and she wants to once again put a stop to it?
But we cant say for sure that its the Derelict..... other options could be..
1) LV-223
2) David 8's Juggernaut
3) Another Juggernaut from some place else
Another thing to remember was that Alien 5 trod on the toes of Prometheus 2 in regards to things that movie would cover... this has to be regarding either or a few of.
a) What remains of Engineers Ships/Technology in the years 2179 - 2200 (is the Derelict the only one left?)
b) What remains of the Xeno DNA by the years 2179 - 2200 (again is the Derelict the only source?)
c) What information is known about the Engineers and their Technology Post 2179?
d) What other kinds of Xenomorph or means of manipulating the DNA are there.
e) What connections do the Xenos have DNA wise to the Black Goo.
I would assume one or more of the above may have been explored in Blomkamps Alien 5 and so they would have to first change some elements but also maybe push a Prometheus Sequel out first to touch upon the above, so that Alien 5 has freedom to explore these without spoiling the Prometheus Sequel..
Maybe this is why the U-Turn.. maybe some elements from latter in the Prometheus series have had to be brought forwards.
The source who gave supposed leaks to Paglen/Green Draft of 2014 did on one of the last times they mentioned the movie... that it seems prehapse they are re-arange the planned Story they wanted to tell.
i.e Prometheus ==> Part 2 ==> Part 3 ==> Alien in a A-Z Fashion. They said it would be like Star Wars planned 9 movies, a EP 1-9 in a A-Z Fashion but we never got that... what we had was a EP 4-6 then a prequel series 1-3 and then sequel series 7-9 and by watching the movies when complete in a A-Z Fashion would leave some elements of the later movies as being no surprise.... So they are implying that elements to be covered latter in Prometheus Trilogy may have been altered and brought forwards and a new Plot also thrown into the Mix...... a bit like say how Star Wars Rogue One will be to EP1-9....
This is why they wont give no information as they claimed they dont have none really with Covenant but there could be parts of the Paglen/Green Draft that will feature in Alien Covenant and its sequel...
I will put down and update the only and last information they said, but we cant proof any of it now unless Covenant and its sequel use some elements or we manage to see Paglen/Green Final Draft released.