Doors is interesting.
There is normal way (go through and hold for person behind so it doesn't slam in their face) and "gentleman" way where a man sees a laydee approaching, holds in open and ushers them through first.
I find this irritating (minor) as it's one of the small things that reminds me that while I'm going around feeling like a person, a man decides to remind me that I'm a laydee.
The men at my work are big on this so I have been fucking with them a bit 
when I get there first I pull the door open and usher them through with a cheery "after you!". Rough estimate on results - most look a bit surprised then bimble through. About 1 in 20 or so (not actually counting ) REFUSE. They literally say no. There have been stand off. Most end up going in a slightly huffy way as I'm holding the door and they really look silly. A couple have refused outright. They literally refused to walk through.
So, for men then, some of them anyway, this door holding lark has something going on more than just a bit of courtesy!
The other thing is you canbet none of the "gents" who make sure it's ladies first at the work lift would e.g. do it when catching a crowded commuter train, something tells me that they would have very sharp elbows indeed.
Anyway writing that I wonder if this is what is going on with some of it.
I wanted to be seen as a person and I was always seen as female FIRST, and then there were a whole bunch of expectations overlaid which usually didn't fit me, so I became a feminist. When I was quite young > I always thought, we should all be treated as people with no assumptions about what we like, are good at etc etc
So now, if I was young, would I say, I am being treated as the female gender, this is what most women want, to be recognised as female and then treated in a certain way. I don't like it, therefore I opt out. I'm non binary or something and I don't want men treating me "like a lady" so I need different pronouns and to tell everyone I'm non binary and then it won't happen and if / when it does, I will be very angry and upset.
This is a poor solution though surely? Structural sexism is not tackled at all, and if the person is recognisably female they will still get the sexism whether benevolent or otherwise, and spend all their time being pissed off as you can't really "opt out" of your sex, and it's sex that this is all about.
All those questions about being treated as a certain gender / expressing gender through clothes were a bit weird. Most people feel like people, surely? Hard to say > I know that's how I feel.
The questions were so weird. Would it cause problems for parents if a gender (sex?) is not "assigned" at birth. No? They will know what sex it is. Humans have known what sex their children are since before we had governments and hospitals and things...