Se, ze and zir are the most "conventional" nuetral pronouns, but lots of people just come up with their own, like squee, and squir.
Also, I wonder what other queer languaging exists to de-fang the soul-eating bite of English. I've realized recently that these kinds of things express vital parts of E-primitive, and it really got me excited to realize folks started this work long before today, without any notion of rewilding or collapse.
I'm not sure if I understand you question, so let me know if I'm totally missing the mark...
There is the issue of how folks place validity on certain expressions of gender through language.
An obvious way that people do this is by using the term "real woman". This implies that trans women are fake, not very nice of course.
A more subtle term used within my community is "bio", sort for biological, added on to the front of gender. For example "bio-guy" as opposed to "trans-guy". I personaly don't use this distinction for a few reasons, the main one being that we are all biological, right? I mean if I'm not biological, what am I? Science carries a ridiculous amount of weight in our culture. I think "biological" means "valid" to a lot of people, and "trans" is an interesting theory to be dissected in debate.
I use "trans", and "non-trans", lots of folks dismiss it as cumbersome, but it uses exactly the same number of syllables as "bio".
That seems to be a huge problem with changing the language we have grown accustom to. Of course
it seems cumbersome and forced, learning something new usually is. It begins to be natural, but not many people are driven to give it a shot.