You'll be able to challenge us gym leaders using whichever team you choose, even though we're still debating whether we'll have some restrictions in place to make sure people can't, say, bring a team with six water pokémon on it to the fire gym.
This reminds me, we should probably do as in Pokémon Origins, and have some not-so-competitive teams in place for less experienced players. It'll probably take us longer to raise, but at least we won't be mass-hatching for perfect IVs, HAs and all that. It'd be the perfect place for me to use my shiny Venomoth in (<3) without it being ridiculed by way stronger pokémon.
Yeah, we're all monotype, or themed stuff, such as my bug-type gym possibly having bug-type Skorupi's evolution, Drapion, in my team, despite it dropping the bug type once it evolves. We'll all have to get creative with ways to waltz around our glaring type disadvantages, so it's going to be fun for us as well.
Team update: Nearly got my second team member, Larvesta, ready! My latest 4IV parent is being ravaged by god ditto as we speak, at least until I get a 31/xx/31/31/31/31 IV spread. Is it me, or does the Everstone also lock a pokémon's ability? I think all the scythers I've hatched previously have technician.