I mean, it depends on how you define species. If we have a morphological species definition, then appearance is everything. Does individuals that look very similar, have similar dna and can have fertile offspring not count to the same species if their behavior is different?

Is the cat ok?

Idk. There have been cases where people have regretted having the treatment. They are few compared to the number of people who think that the treatment was the best thing they ever did, but they do exist. I guess that being trans might cause some effects, like people being mean and bigoted or just the stress of knowing that you don’t fit in to what society seem to expect you to. I think prioritizing mental support through therapy might be a good start before the physical treatment. It will be good for both those that would regret the treatment but also for those that will get all sorts of weird interactions with others during the transition.