Emma does seem to have magic or at least her actions are causing magical things to happen, the clock ticked, the mines caved in, the hat worked. There is something going on there that is more the accidental. We have no idea how someone becomes magical in this show.
In Stable Boy it doesn’t seem like Regina has any magic, but she clearly does later on so somewhere she must learn magic or take it from her mother. And Snow seems to have blue birds that will come to her which seems magical to me. They have mentioned using the blue birds to send messages many times and have shown her with blue birds i think three times. And also the pigeon brought her the letter from Charming.