No, no, no, and yes. Actually, they've already had a sort of world from stitch in bbs (it was a spaceship, not a world, but whatever). What home world would you use from stitch? Hawaii? I can't think of another world that fits into the story of lilo and stitch (there were others, but stitch goes straight to earth after escaping from the ship that was in bbs, although they could certainly stray from the story of lilo and stitch).