Watching the videos and such it looks like the limiting issue will actually be the dimensions with the doors open and not the floor size.
Promotional materials have shown the Gladius (20m x 16m x 5m) and the Sabre (26m x 24m wings folded x 5m) deploying from the WarChip Hangar Bay.
I am betting that an Aurora will fit (possibly 2 but depends on how they use ItemPort to secure a ship inside a ship), a 300 series probably, SuperHornet probably, SpacePenguin for sure, Gladiator probably, maybe even a Freelancer.
The Vanguard by comparison is 37m x 25m wings folded x 8.8m, and the Redeemer is 37.5m x 19.5m x 11m, so doubt they will fit (but would love it if a Vanguard would fit, Hoplite module in a Vanguard would be awesome popping out of a Polaris).
'Gimp