I appreciate your research on it. So that means although the National Pokedex will not be displayed, the data of the Pokemon(like Charizard) has already been registered? I didn't genned any theoretically illegal Pokemon but also got banned. Also I didn't participate Rating Battle and online competition. I don't think this will have something to do with Pokemons. The only I can do is clear the Pokedex, Items and change the game sync id....Anyway, thank you.
I also genned complete National Pokedex and got banned. Could you please check your Moon's Save Data? I want to see whether Pokemon not belong to Alola Dex will be registered. I doubt that what cause the problem is not The National Pokedex but Marshadow's Dex Data. Thank you!