I’ve always considered Mulan to be one of Disney’s bolder movies. I know they are following the traditional legend, but Diseny didn’t shy away too much from the more liberal topics.
But is it a message of transgender people? I don’t know. I’ve always seen Mulan as less about Mulan wanting to change herself and more about Mulan wanting to change society. It’s not that Mulan wants to be a man and dresses as a warrior because she feels it is who she really is, but rather because that’s the only way Mulan can play a part in society and save her family. Mulan deals a lot with gender and society, which is still a pretty heavy topic for something like Disney to take on. But I do think you’re right that Mulan’s more fluid nature between “masculine” and “feminine” is what inspired A and E to have her falling for Aurora. I really *really* wish we had an episode dedicated to Aurora and Mulan’s adventures in finding Philip. It would be a great episode to explore internal conflict: Mulan is falling for Aurora, but wants to save Philip who is Aurora’s true love. If anything, Mulan certainly has more integrity than a lot of other characters.
After all, if the writers didn’t really want to introduce an LGBT character, why write Mulan as one?
A lot of it was subtext I think (though it got heavily more “text” as S2 went on and then into S3). But like @Myril said a page of so back–you still have tons of people denying that Mulan went to declare her feelings to Aurora, they think she went to talk to Philip. So as to the “why” well….because the writers aren’t stupid. Philora fell flat in a lot of ways (lack of screen time together, for instance). But SleepingWarrior took off like hotcakes. The writers aren’t 100% ignorant of social media and what is considered popular. They had to hear enough about SleepingWarrior that they were clued into how popular it had become. BUT A and E like their Disney couples to be canon and so they threw the audience and shippers a bone, and then took it away. I really wish Jamie would come back so we could see how Mulan is coping with her unrequited love and perhaps her growing sexuality.