about oshawott

[Might Gai 63]

Spoiler

we all know popplio replaced oshawott

and i heard that oshawott is now the prize for the magma gang quest alongside litten for the aqua gang quest, but, does that mean if we pick aqua for example, we don't get oshawott, if so why are they both not listed as limited events in the obtainable list ?

[gkhmpg 11]

Quote

* A limited event refers to a scenario in which one must choose between two or more Pokemon, the others becoming unobtainable (so far), such as choosing starters.

In the case of the gang's mon, we can get the other one later in the game, I suppose.