Well, if we assume a big-crunch outcome of the universe, then it could be said that all matter would end up inside 1 big black hole. And then it might follow th

Well, if we assume a big-crunch outcome of the universe, then it could be said that all matter would end up inside 1 big black hole. And then it might follow that the universe is re-spawned inside of the black hole. This solves your 2 issues, all escaping material would be re-absorbed, and there would only be a background oscillation of energy in and out of the universe that would net to a constant. This example kinda kills the whole romantic-fantasy element of universes in black holes, since you would only get 1 child universe per parent universe, and it would not really be noticeable from our point of view. (what happens to those poor universes when 2 of the black holes combine??)