The basic problem with gay conversion therapy is the subject choice. Everybody naturally falls somewhere on the Kinsey scale between 0 - total heterosexuality and 6 - total homosexuality... folks in the range 1-5 have some degree of choice while 0s and 6s don't. the folks targeted by gay conversion therapy are usually obvious homosexuals in very religious families... these are typically Kinsey 6 types who have little or no choice in their attraction or (given the environment) they woulda simply chosen to be straight. Also, these subjects tend to be relatively unwilling and doing it to please others or avoid consequences. Not exactly the most conductive situation for lasting change.
The folks who do a gay conversion hypnosis like my
Shattered Heterosexuality system are typically Kinsey 1-2 guys who have a significant desire to turn gay already. These are subjects who do have some degree of choice and a desire. Still doesn't work on everyone: out of 200 subjects I have seen 2 failures, one from incompatibility with prior hypnosis, one because the guy was a true Kinsey 0 doing it on a dare who didn't really want to change.
As for transgender hypnosis, it's a commonplace. WMM is chock full of sissy hypno, and more serious m2f and f2m sessions happen in hypnotherapist offices all the time. There's less around for f2m, but my
Masculine Conditioning system has been used with success by several subjects who were assigned female at birth to turn male; and by several ex-trans guys trying to escape sissification hypno, albeit with mixed results.