How many Son'a are there?
I don't know if this has been talked about, but the Son'a are supposedly a group of former Ba'ku who failed to launch a coup against a village with roughly 600 people. So, presumably there can't have been a great many of them to begin with.
Yet, within 100 years they managed to form a civilisation capable of conquering other races (even pre-warp) and developing this highly-advanced technology beyond even the Federation. Unless they breed like rabbits, was that meant to be their whole race in that fleet in the Briar Patch?