I broadly agree, but I'd more strongly emphasis the influence of post-pubertal social failure. This isn't really related to over-protective parenting or anything, but rather to the underlying psychological abnormalities present in a lot of troons. Autism or at least spergy tendencies loom large here. For a lot of autists, the end of childhood proper is difficult; they struggle with forming or even understanding romantic and sexual relationships, they often get bullied for making faux pas and bullying in general increases massively at around the same time.
Great write-up, very interesting. I don't think autism is the only factor at work; many who go trans are autistic but many more aren't. Labelle and Stefonknee don't show many signs of autism, for instance.
First, my read on Stefonknee. Paul Wolshct grew up Catholic, got married and had 6 kids. I suspect he spent most of his life reflexively following the norms of the culture he lived in without much thought to what he wanted. He started a family and played the part of the responsible father because it's what he was supposed to do. As his family grew, the pressures and stresses increased, as did a question in the back of his mind about if this was what he really wanted.
At some point he tumbled down the rabbit hole of sissy porn. The part of the fantasy that appealed to him the most was being a little girl with no responsibilities, and thus Steffy was born. His crazy destructive behavior was the eruption of a lifetime of subconscious resentment toward the culture he felt he had been forced to go along with.
Labelle seems like a case of arrested development and denial. He was groomed by an older man, developed an attraction to men but can't bear to think of himself as gay. His child characters are an effort to live out the perfect trans childhood he didn't get to have, and now we know that a lot of his fantasy life, sexual and otherwise, is focused on returning to infancy. What I take from it is that his sexual traumas, probably combined with other bad memories, have made him want to flee from his reality as an adult gay man and return to childhood, the younger the better.
In the case of autistic troons with more "typical" trauma from puberty I can see your model checking out, but I don't see how it applies to the many men who are married with families and suddenly fall into fantasies of being a teenage girl or a child. Plenty of the younger transitioners also seem to have normal lives and healthy relationships before trooning. The desire to be extremely young, even prepubescent, seems to cut across different transgender psych profiles, you can see it in a lot of the trans widow stories.