I feel like it makes sense if we don't assume this "leaked" banner is final. Obviously there's something in there causing insiders to doubt it. If it's all Incineroar, then perhaps he'll be a late addition (I don't think there's any reason to assume they just forgot a Pokemon and wanted to add it later--I mean, later than this banner) or DLC. What does make my eyebrow raise is SpawnWave saying it's a character outside of Incineroar causing him to think, if real, it's not final. Not to mention Mystic claiming the possibility of 7 characters, but 3 of them echoes (I find it hard to believe Mach Rider's an echo, but so is everything else) or just 3, in addition to a unique reveal with two characters (whether it's two unique characters, or 1 unique 1 echo, is left ambiguous). I'm not taking the last one too seriously, because I don't quite know their track record and backtracking is always a bad sign, though transparency is appreciated.
I feel like for any type of consistency, one or more of these rumors/leaks has to be wrong.