Which water type?

In route 2 they say that staryu, marill, totodile, and buizel are available for a water type placing in a team of 6. Which PKMN should I aim getting for suntouched?

For your point in the game, Marill is by far the best. Make sure you catch one with Huge Power otherwise it won’t be very good. Azumarill is bulky, has a good defensive typing, evolves really early, hits really hard with Huge Power, and learns strong moves early by level-up.

Let me explain why I don’t think the others are as good for you.

When you evolve Staryu, Starmie pretty much learns no level-up moves, so you’re either going to be stuck with it as Staryu or you’re going to have a really bad moveset. You could Heart Scale Hydro Pump onto it but otherwise it has like no coverage.

Totodile doesn’t learn any good Water-type moves for a long time. You’re pretty much going to be stuck using Brine for a while, which isn’t that strong and the Totodile line is primarily physical attackers. For your point in the game, I think this is the third best choice. You get its Mega Stone fairly early in the game, but it’s pretty mediocre for a while.

Floatzel is just not a very good Pokemon. Its Speed is good but its power is just alright, and it’s frail. This is the worst of the four.