Why not just change the idea to follow on from AR?
Ripley as Ripley 8, Hicks as Johner, Bishop as Vriess, Newt as Call and The Company as USCM?
A quick rewrite could make it all fit.
Honestly if they are dismissing 3 and 4 I would prefer at least an acknowledgement of a bad dream or something. As cheesy as that is, at least it would not render those films completely useless. Alien 3 is imo an excellent film, AR less so but still has earned its place in the Alien canon.