Rex Double Regen
I've been thinking about this, too. The rebel tie will be the key piece in this point range the rebels lacked so far. This is the loadout I'll try:
TIE Fighter: •Ahsoka Tano (24)
•Captured TIE (1)
Sabine's Masterpiece (1)
Veteran Instincts (1)
Recon Specialist (3)
Black Market Slicer Tools (1)
A nice support ship and ace hunter.
Rex might be worth it too, for disruption and as a pseudo-Biggs. It'll probably be best to keep him very light.
I agree, keeping Rex light is probably the way to go. C-3PO on Miranda will work well and make her a bit more durable. This will leave you with a 1 point bid which might come in handy against lists that use their full 100 points.
The other upgrade worth considering is Conner Nets as they can really mess with certain ships.