(Laser is permanent if it kills a hair follicle, but they can't guarantee killing all the follicles.)
I went to Brassard, and he says he scrapes the skin before inverting it into a vagina, so obviously no electro needed - in fact, he says hair removal is *contraindicated,* as it can make his surgical hair removal less effective. I have heard of other Brassard patients say they do have some internal hairs, but personally I do not; I have hair where I'd expect it to be based on cis women (outside of the outer labia, and of course the pubic area), and exactly one annoying little labial hair near the vaginal entrance that curls over and pokes into it sometimes, but that's it.
(Happy to answer any other questions you have about Brassard, too. I'm well satisfied.)