[@LeeRoy], the main idea of the multiverse is central, but there's still plenty of room for convoluted plots and ulterior motives. A civil war happens between Ruling Candidates, for example, as they have power struggles.

VSauce on youtube has interesting videos about infinities and whatnot that you should check out. 

My multiverse can link itself to any of the vast realities, but they're not anywhere close to all linked and might as well not exist as far as the multiverse concerns itself with, so although possibly infinite large if it took in everything, it is not in reality. For example, there could be a reality where a superman-like figure flips a coin and in one reality it's heads and one it's tails, but that doesn't mean both realities can get into the multiverse and you have two super men joining the fray. It mainly connects to main branches of things rather than offshoots, so it could decide on the reality of him flipping heads as the main one connected to the multiverse and you're stuck with that specific version of the super man. There are multiple different versions of earth (earth being nothing special) and other planets, but on a limited scale where drastic changes happen, like if dinosaurs never went extinct, so the odds of two Evvies showing up from different realities of her world are slim, and if they did would likely be vastly different. Some people can force connections/take one way trips to non connected realities, but this is difficult.