Smudger9, since it’s clear to me that episodes 6-8 won’t have enough material for 2 and a half hour movie, you could use the Mandalorian s02e05 footage you cut from your second Mando movie “Search for The Jedi” at the beginning of the second Ahsoka movie.
The confrontation between Ahsoka and Morgan could serve as flashback that Morgan would think about during the travel to Peridea, which would reveal how Ahsoka arrested Morgan and thus stretch the footage a bit.
We saw something similar in the Halloween Kills, where at the beginning of the film, thanks to a flashback, we found out how the police arrested Micheal Myers.