Latios is perfect for fluffynite, actually so good that it might give the deck some wings. Lisia is pretty bad because right now prism stars are all supporters, which can't be played the same turn you play her, or pokemon, and most decks just run one prism star poke if any.
Steven is good without N around, similar to Kiawe for fire decks as a t1 supporter but for every deck and will be some competition for Lillie for that turn 1 supporter use. It's especially good for stage 2 decks since it will easily get you candy + stage 2 and then either an energy to attack with it or a Cynthia to shuffle your hand.
Altaria-GX is a pretty solid card as well, keep in mind we get fight song Altaria too, which will easily let you get to 120 damage for 2HKO on most of the meta.
Blaziken-GX is obviously intended to work with Champion Road Blaziken. I don't think it will be that great of a deck considering you can hit that number more consistently with a stage 1/basic combo, but it will be at least playable.