I last played Omega Ruby/Sapphire. I gotta look into this pokebank stuff tho, sounds cool! thank you.Just Ultra Moon is fine. Tbh SM look like beta releases compared to USUM. You can transfer Pokemon through PokeBank, which is available after you get your Pokedex IIRC. As for breeding competitively, I have no idea lol. And in regards to starting out with perfect Pokemon, you'll need some perfect Dittos to breed them, which are given away by many different users
Which was the last version you played in?