Using Rogue One footage is dumb because it’s very clearly set during the OT. There’s no way to remove all the iconography in a way that would make it plausibly pass off as being in the ST era.
To be fair, the ST already has a lot of iconography and weapons/vehicles from the OT (X-Wings, TIE Fighters, Stormtroopers, etc.) It would be slightly difficult but I think someone could feasibly pull it off.