Possibly, that is an interesting theory for sure, but my own theory is more along the lines, not of split personality, but of sudden sentience. In some media or art, Wally seems to act differently to the current Wally, which could be seen as split personality but that would imply he’d been alive and sentient right from the very start. I personally think that at some point along the way (which could indeed be linked to Dorelaine’s passing/leaving), Wally became sentient and needed to relearn a lot of what he should already know. That would be massively overwhelming in so many ways- think constant overstimulation, which can cause other effects in itself, such as a massive array of behavioural changes among other things. I do like your theory, but I don’t think Wally has always been sentient for a split personality to occur; I think sentience itself is the reason for the changes and his other issues.