I'm going to respectfully disagree w/40Driggs on the 8' thing...its just not always possible. However, you can still get a 2-3' distance, maybe 4' from the background and have good separation. I'd try to shoot with a smaller aperature so that your depth of field will be larger.
Definitely check out the zarius tutorial that someone linked you to a bit ago...its wonderfully helpful. And then, even if you have to use a teddy bear or something, give it a shot...just practice a bit until you get your lighting tweaked for your space.
I don't love the angle of the 4th one, just because its sort of "looking down" Mom's shirt...its not a BAD picture, its just got a bit of room for creativity.
Overall, you've got a good first start.