I don't do an transition period. every kid I have gotten has started off "cold turkey". It just always worked out that they needed the spot and there was no time to transition the kids/parents.

personally I wouldn't do it. As for the parent coming early, don't really see how this would help the kid since the mom is there. If you are ok with the mom being there and the mom wants it, then I don't see how it would hurt, but I really don't see how it would help either. The kid will see the mom so will not be focus on you or the other kids the same if the mom was not there.