If the film does well then maybe a new tie-in game, or update of the old RS games too?

Factor 5 being dead for over a decade doesn’t help matters much in updating the old RS games (i.e., the source code is probably lost). If the code still exists, a publisher could port the game to modern systems, a la the Jedi Outcast/Jedi Academy and Republic Commando ports. If it doesn’t, a ROM of the original games running in a distinct Gamecube emulator would be acceptable.

We’re long past an age when Dolphin Emulator would turn into into a potato at the mere mention of the Rogue Squadron games.