From our original list we only have four left:

Aunt Beru Lars (with baby Luke Skywalker)
Uncle Owen Lars
Senator Padme Amidala (hair in buns..."Annie, I'm pregnant.")
Padme's birthing aide droid (Polis Massan - "Uba....Uba.")

It seems to me that Beru and Owen should come off. I know that you can argue that the outfits are mildly different between Owen and Beru in AOTC and ROTS, but I really think they have made the figures now and that a ROTS resculpt is very, very unlikely. I would assume most of us would be willing to put AOTC Owen and Beru into a ROTS homstead diorama.

Anyway, if the rumor about the birthing droid is true, that would just leave Senator Amidala from our original list of 20!