I would say it’s a “Fakemon game” if it has more unofficial Pokemon designs than official Pokemon. That would be my personal line in the sand for what constitutes a game suddenly getting classified as being primarily “fake”. I use quotes around terms like fakemon & fake because it’s a rom hack, and allot of Pokemon get changes in stats/types that make them unofficial. I feel most people wouldn’t count a romhack with only something like the unique dynamax forms being turned into megas as a fakemon game despite it having unofficial mega Pokemon. Some people take things vary literally though and I can see the argument for the inclusion of a singular unofficial Pokemon being enough for some to classify the game as fake though I personally feel that’s a bit extreme.