Board Thread:Questions and Answers/@comment-27766744-20160525044527/@comment-16461120-20160531211149

In it notes that everything and everyone that became part of the amalgamated Weirdworld did so as Battleworld was being formed, so think of it as adding things to the pocket dimension, which existed prior to the collapse of the multiverse, then like a magnet it drew all of bits of magic from all the universes that Doom was manipulating as if they were a bunch of iron shavings pulled unto itself.

The Witch Queen may have traveled there before or after Last Days, but it doesn't particularly matter, and she appears to recall everything that happened during her over eight years in Weirdworld. I don't believe Reed recreated it, rather it simply exists on a different plane than the rest of reality, and a portal there was just revealed to have been in the Bermuda Triangle for quite some time in.

If there is a plot reason for universes to remain destroyed, then I imagine they will remain destroyed, and vice versa on their restoration.