I'm new to the whole FFG community, so thanks for having me, but I am a veteran TCG/CCG player, and I apologize up front if these questions have been answered:

Is there a way here to find stores that support the game/have tournaments to participate in?

Also, with the deck building rules being that you can play 2 of each objective set, do you technically need 2 core sets?

Is there a way to play this game online? I heard Octgn is used (which I havent used in forever and would need to find it) so are there rules for using it and downloading it? Places to play?

You don't technically need two core sets, it's entirely possible to build legal decks with just one, but you'll want two core sets if you want to build competitive decks. You won't need a third, though.