Look, this talk of "outside the universe" and "other universes" is bunk. The term "The Universe" is the designation for ALL there is. There is only ONE Universe. That's why it's called The Universe. If something is outside the Universe, it doesn't exist. Heaven is indeed within the Universe. If Jesus is alive physically, He's in the Universe. If He's not in the Universe, then He is a spirit and all of the things concerning eternal life, as related in the Bible, are untrue.
Then where was God before he created the universe?