Question

I was watching meloetta and the undersea temple and I noticed oshawott was (technically) infituated with meloetta when it wanted to battle (scary enough its genderless...)

Answer 1

The show and the corresponding movies works differently than the game does.Which can never happen in the game series.

In other words Meloetta is a girl, but is not stated in the game.

Note that a female voice accompanies only feminine looking Pokemon in the show and movies.

If I answered your question then put it as best answer if not comment and I'll try to rewrite it.