I think she moved her nest to your sister's room, so you might want to put whatever blankets you have for her in there. It sounds like it's warmer in there anyway. How old is your sister? Will she bother the kittens?
Not normal, but not uncommon either.It is not normal for kittens to die, though there may be a runt that needs extra help from you.
Any kitties yet?what signs did your kitty so???