The mini-expansion you propose would have 2 Masters, 5 Sidekicks, and 3x12 Pawns, plus Teddy = 44 models - same as the current starter. I'm good with that, but it's not any smaller than Unstitched. It's really more of an alternative starter.
Definitely need at least Teddy in any expansion for how hard they were to get in metal. I am not happy that they were so rare - someone who bought all 4 of the expansions should have gotten at least one.
With basically a full starter's worth of models, a different-shaped board would be nice, perhaps 12" x 18", to enable different scenarios.