The Corrin Amiibo is gonna be Smash-based, so we'll likely get Male Corrin as the default. Of course, we could very well get both (I recall there being a listing for an unspecified Amiibo two-pack) if Nintendo intends on selling alternate variants of existing Amiibos.We'll probably get Corrin amiibo.
Hopefully female is the default.
That said, don't expect any Corrin Amiibo news until Smash 4 Switch is revealed.