Given how significantly most of these people have aged, I wonder if an animated film or TV series would be a better idea if someone decided to pursue this project. I've no interest in seeing Frakes strut around with his huge beer-gut, but I'd be okay with him voicing an animated Riker.
In theory they could do anything
with the help of animation. It could even be set pre-Nemesis and actually incorporate Data in the cast too, because Spiner's concerns about being 'too old' to play an ageless android would be very easy to fix in animation. He would just have to sound
What cruel statements these are, dudes. How dare anyone showing his old rotting body in my entertainment?
Spiner's concerns were that Data (the specific character) is ageless, but he himself isn't. And that is a valid one. But he would be quick to tell you to fuck off if you called him too old and ugly and bloated and whatever the hell people regularly call old actors.