I almost forgot about SimEarth. For some reason I was allowed to play it in grade school computer lab. I wish they would remake it so I can recreate my sentient cephalopod uprising, except with graphics that aren't complete ass.
I never played SimLife. But no, Spore is really not like SimEarth at all. As the other person said, Spore is disappointingly shallow on all levels.
Most likely yes, as many others have said. Of course you'll likely have to pick a very lightweight DE.
As a fallback there is always NetBSD.