Sounds like a mess of epic proportions, that alone would make it fun. But I don't see it, almost impossible to properly integrate it into the story. It has characters we already met, but different and in live action. I could see it if Quadratum wasn't simply a different reality but a mirror world with mirror characters, but it doesn't seem like that way now. It seems it will be a reality with live action worlds, and the familiar characters would be out of place. It won't work with Sora's reality for the same reason: familiar but different characters. Are they the same? Why are the characters from different worlds are in this new one? Or are they separate?
Maybe, if the PoHs goes to Quadratum, we will see them modelled after their Once Upon a Time appearances.