Please don't get mad at me

Well, The first thing you need to know, Their gender is not related to their sexuality at all

And here's your answer:
If a trans (Male) likes guys, It would be a Trans Gay relationship
If a trans (Female) likes girls, It's a Trans Lesbian relationship

If they like someone who has the same Sex (For example, Trans Female and Cis Male) It would be a Trans Straight relationship

It's more about the "BODY" then it is about what's in the pants

it still can be if you have declared your gay

It can vary depending on how the person specifies their physical attraction. I think most trans people identify their attraction based on their gender instead of their sex. But I have seen some trans women call themselves gay when attracted to men. That may have changed since, it might change depending on how far along a person is in their transition, I honestly can't say - especially since the answer varies from person to person. I'm not sure I have ever met a straight trans person though - they all identified as either gay/lesbian or simply as bi/pan or ace.

Was this just general curiosity or is it about someone in particular? Because if it is about a specific person just ask them how they see it. And if this is about yourself, just see what feels right to you - there is no right or wrong, you're not "less trans" if you identify your relationship based on sex rather than gender, you don't have to be a certain way to "do it right".

long story short, if your a trans woman(or a man that became a girl) and you like women it is her being a lesbian
if a trans guy (a girl that turned into a guy, like me) is attracted to males they are gay.
in this essay I will-