Mulan is definitely a top, and I like to think that a lot of her and Shang's couplings begin with tussling or sparring or something like that. Like, war is something that is not pretty, but actually sparring gets her in A Mood. Plus sweaty Shang, man, who wouldn't go for that. Definitely genderfluid, possibly into fetishizing being masculine and I can sort of imagine some roleplay going on in there. Not revolving around the whole 'punishing a lower officer for doing wrong narrative, I think that'd make her uncomfortable.