Unless Tsubaki turns out to be female(or I learn beforehand that his personality kinda sucks and the rest of the Hoshido boys aren't really cute enough), I'm going female. Gender has zero effect on relatability for me when it comes to characters that aren't specifically written for the purpose of showing the problem with social pressure via gender roles (and even then I might relate more to the girls BECAUSE REASONS) and I really doubt that My Unit of all people would have those kinds of issues. It becomes a problem when characters are too relatable too.
If you are going to let me make a personal character in a Fire Emblem game where there are supports AND where I will be pairing up all day AND where Awakening pretty much foreshadows having moar self-insert shallow romances, then this kind of thing is more relevant than ever.
Also unfortunately 99% of the time twintails are not an option for male character creation.
Probably male, though if the portrait is the same a the one in the reveal trailer I might go female. That neck was just so weird...
There is probably the existence of multiple body types for My Unit.