Genderless pokemon cannot produce eggs. Therefore, genderless doesn't match with some pokemon.
For example, you want a genderless pikachu. It's data does not have "genderless" <_<
And if you were to put genderless pokemon into the daycare, they would produce no egg. *obviously*
If genderless were possible for all pokemon, then pokesav would have it. <_<
BUT, with rom hacking, it is possible.
EDIT: Oh, I forgot about the first question. For some reason, Aipom seems to have two slots, not one.