I think Protocol droids and R2 units could be passed off fairly well and quite simple
they most certainly would. hasbro could do a variety of multipacks utilizing the R-3PO and K-3PO sculpts for protocol droids and the various R2, R3, R4, & R5 (Star Tours) for astromechs. any combination of droids would work so long as no two sets had the same colored droid in it. imagine these 4 packs:
1.) 2x 3PO units, 1 R2, 1 R4
2.) 1 3PO unit, 1 R3, 1 R2, 1 R5
3.) 1 R2, 1 R3, 1 R4, 1 R5
4.) 2x 3PO units, 1 R3, 1 R5
that would so totally rock!