Well, ah, about the gender vs sex thing, as I always thought that Tauros had a counterpart in another pokemon species- eg miltank, I kind of thought Revel's Tauros was a male assigned Tauros identifying as female.
When it comes to really deep emotional details and preferences, I would not think things like that would go on certs because they are often very large- imagine if we had a genderfluid pokemon- what would we put on their cert? And would everyone understand it, even lay people? Those kinds of things are best in journals or spoken to in person, if a person wants to rp with you, they will learn even if your journal is out of date. If they want to breed and you're like 'Thanks for the offer, but nah, my pokemon identifies differently from their assigned sex' then you're going to learn also.
Slightly irrelevant, but did you guys know that two male swans will kick a female swan off her own nest to brood on and hatch the eggs and raise the cygnets? One male in a lifebond with another will even breed with a female and then attack her until she leaves so the males can raise it!
*Two male swanna with ducklett* ^___^