1) I believe the difference is non being they can't think like a sentient would, whereas semi can sorta think that way, like they have a slight inclination to think the way a sentient would. I'm not completely sure though.
2) You could always just put that they have no tech level whatsoever. As for culture, you could probably put their habits there. For instance, how they hunt, forage, that kind of stuff.
3) Home world can be any planet, though I suspect if it's custom, you'd need permission of the creator of the planet.
4) Wha..?
[member="Arumi Zy"]