First off, dont be so biased against Enix. They came out with some amazing games in their day. And there's a lot of good RPGs made by other companies you should check out. Anyway.
a) Um... RPGs? What kind of explination do you want? Xenosaga isnt Square, it's a fun game though (too many FMVs if you ask me), and from what I remember Xenogears was only liscensed by Square, not made by them.

b) Final Fantasy Athology, Chronicles. As far as I know those're the only FF ones, aside from Tactics, not released in PAL region. I dont know which were and werent, so Im just gonna list what I can think of off the top of my head. And Im not listing only Square, cause that's silly. Breath of Fire III and IV, Star Ocean 2, Wild ARMs 1 and 2... hm... that's all I can think of, I think.

c) They live on the moon.