At the VERY least, Maginary World would become larger. Since there would now be an infinite amount of sentient beings accross an infinite amount of infinite sized universes adding dreams to it at every point in time. The thing you already said in your last major Archie cosmology revision basically. If we account for the string theory arguments, (which in my opinion, warrant at least a "possibly" ranking), the main universe would be High 1-C (11D), Maginary World would have to be a level above that since each dream world in it would have the same scope as the main universe, including
Boom Eggman's dream of proving himself as the greatest scientist in the world by showing off his artificial black hole created using
his studies on string theory. Then, you still have the hyper-timeline, making the cosmology as a whole 1-B (13D).
I may be an insane for proposing what I just did, but this is pushing it imo. This results in too many inconsistancies and would only make sense if all of these continuities were connected to the pre-Genesis Wave multiverse, which they have no logical reason to be.
By the way, this revision won't be attempted before a while. I'm just giving you a peek