Lesley for a girl; there was a moment in the 1950s when a lot of little Lesley-Anne girls appeared, which I assume was an attempt to make it sound less unisex; also Sally-Anne etc, so the combo was fashionable. But since unisex is viewed more positively now, I don't see why it shouldn't make a comeback ... except that it does sound and look rather like
Lindsay, which might make people identify it with that kind of flash-in-the-pan name and avoid it.
I can see it on a baby very readily!
Do you pronounce it LEZ-lee or LESS-lee? Where I live it's with a Z sound.