Hijab and Nonbinary People?

Hey guys!

I'm not Muslim, but I'm writing a story featuring a hijabi woman and a genderfluid person, and I'm confused as to how the rules of interaction between men and women apply to said genderfluid character? I'm tempted to err on the side of caution and have the genderfluid character not do things like see the hijabi without her hijab or hold hands with her, but I'd like to see actual Muslim thoughts on this?

More broadly, how do nonbinary people interact with Muslim rules about modesty and mixed gender dynamics?

(Personally applicable to me, as a genderfluid person (not out yet though) with a lot of Muslim friends.)