After choosing a Pokemon, in pokemon go, can you collect the other Pokemon that are available at the start?

Yes you can, you can start with a Bulbasuar, Squirtle, a Charmander even a Pikachu and still catch the other starter pokemon. You could also, try to hatch the pokemon from an egg or just walk around and catch them.

Yes either by finding them or hatching them.

There's that guy that was the first person to catch all the Pokemon available in North America so that should answer your question.

Yes. You can catch all of the starting pokemon.

umm...I have been playing pokemon go since it came out and never had to choose a pokemon like you are talking about...

yeah... you can catch all of the starting pokemon...

Yes you can find them in the wild however they're some what rare

Yes you can also find all of the starters that you didn't choose

Yes you can find them but they're pretty rare

No.

no...