But wait, weren't Alpha kids able to interact with Betas despite being separated by scratch? So would it be safe to assume that scratch won't erase other sessions in universe - after all, scratches don't seem to be a linear event? Like, the prerequisite for players in other sessions is already existing - pre-scratch universe "was" a thing.

The Alphas managed to interact with the Betas only in two occasions, one when they actually got past their respective Pocket Dimensions and reach the new Session, and prior to that, sending and taking stuff through Sendificating and Appearifying Technology. The items Jake sent made it into the Session through the Frog Temple machine, but when they were interacting, their iterations of Earth were running parallel and interacting with each other- Earth, not the Session. Similarly, Roxy’s snatching Jaspers from the other Iteration of Earth is a thing linking both Planets, but not Sessions. This is because, in the eyes of the Universe, the Scratch has always happened and the new iteration of Earth sort of happens at the same time as the previous one. It’s unknown if the energy of the Scratch would ALSO affect the future of Alpha Earth, however, since the Red Miles is a way more pressing concern for the people living in Sea Hitler’s Water Apocalypse.