You can't get all of them yet. Sprigatito , Scorbunny, and Popplio are one or the other kind of scenario until further development :(
I know you get your choice of them as you're heading to Rustboro, after defeating the special Raltz and reporting to Whitney in Petalburg. I am rather far in one game, and started a new one, so if this is the one that you get to breed, I do not recall. But, can update you once further unless you reach that point first