The biggest question here is why? That's what puzzles me the most. Why? What purpose does this serve? It's so odd.
We should also remember that this movie may never even be made. But I'll speak as though it is.
Branching universe theory of not, you are in fact dealing with resurrecting characters. Some character who died back in the 90's is suddenly alive, on screen and like 30 years older. For 19 year olds who's first or only contact with the Alien universe was Alien: Isolation, this might not be a big deal. For somebody like me, who's been around since Aliens, seeing these dead characters on screen again will be beyond distracting. It would be like Sean Connery appearing in the next Indiana Jones Movie. If time manipulation or disregard of other timelines is introduced in any fashion, we've moved into terminator territory, and that's a huge step in the wrong direction. Merely in my own opinion.
I mean absolutely no offense to anyone not opposed to this idea of character resurrection, but it's just not my bag. Even resurrection had the decency to make ripley a clone. And Newt, bless her heart, wasn't the best character in the world. Hicks was a solid character, but so were Dallas, Parker and Dillon. The same with bishop and ash. This universe is not conducive to survival. Nobody gets a good ending. It's one of the things I like about this franchise. It's not preoccupied with happy feelings, it's hard grounded. People shouldn't really be expected to survive these creatures. I'm afraid what we're dealing with here is an effort to cater to another sub-group of the fanbase which feels let-down that their favorite characters from Aliens died off-screen. It's just my opinion, but let the dead rest in peace. If they were mentioned in passing in Alien 3, or just went missing, that's one thing. They were dead on film, it's time to move on.
Golly Moses, Ripley and Hicks back? It would be like Cameron making a film called Carpathia and having Leo take that boat instead so they can meet on Carpathia after the sinking and live happily ever after. Strange, just too strange for me.
And by "they" I mean Leo and Winslet, not Leo and Cameron, cause that would be a whole other level of weirdness. I mean geez, talk about time travel elements. That would be insane. "Oh thank you for saving me. I'm a movie Director, and...I love you".