I dont care about cannon or not.
Every "female" character i ever made was trans.
And the other pre created characters?, well master chief is a woman that had to learn to speak manly in order, stop getting extra credit for achieving somthing.
Because for accomlishing tasks equal to male spatans she was met with above and beyond the call of duty, whilst her male counter parts were just doing their duty. And this annoyed her to no end. So in order to truely be treated equal, she hid her femininity. And only johnson and (sorry halo fans) "that scientist" knows the truth

Yes it is a fantasy, but then again so is the gameworld to begin with. Nothing is going to ruin that for me, even if the creators and they do say otherwise. so I can relate to people who wont let their fantasy of samus be destroyed be the creators either. (even if they out right say it)
Playing games and the characters in them. Is about setting foot into an imanginery world. YES the character somtimes has to go through set senarios, nd somtimes exspres some characteristics. But say your character fails to save an npc, does your character cry because sombody died? or because they hate to feel failure? Ther is a lot of ways a player can refine and re-define a character in a game. And I think for the most part the creators dont mind.
Now as for the need for trans character representation, can we realy get that? Short from depicting a none passer in the game? If the character passes, they will be cis, even if the creators say otherwise. We could start of by showing a young boy/girl go though "event" and depict this as a memorry, by fading out the setting as and older vertion of, boy/girl is faded in, depictinga fully passing adult, in gender contrast to younger vertion, this would be met with, I though it was a boy/girl, I must of been wrong.
Point is when we see a gender in somebody any noneconforming atributes get lost in tolerance. Meaning the perceptive boy is re-defined and becomes a perceptive girl that only looked like a boy. (gets frustrated at the prospect of proposing the affect of passing) But if the oposit gender atributes are not in the tolorated peramiters as an adult they wont pass and are transgender this way.
I suppose, we could add, another character into the past and present settings reffering to the younger with one pronoun, and the older with an alternate pronoun, but this would be taken as and older sister thinking about brother. or vise versa. Or the perspective of the third person, thinking back to similer situation that they found themself in with a completally different person.
It would be nice to just be able to say, this char is trans and have people take it as it is, but this will more then likeley result in a game not selling aswell. Or being reduced to the LGBT(any other leters) freindly comunities. And in order to be worth the companies while might have to be low budget.
Idk.
Id just be happy for the trans choice, to affirm my characer Identity, but would we use it? maybe so, but Less so in an online game.