We all know how difficult it is to identify the sex of these fish, so please post a picture in here and we'll try to help you (or at least give an educated guess!).
I'm sorry to say that they look like three males to me. At least they are mature and healthy, if you can find yourself some females you will be good to go.
Sorry mate, I don't know what pictures I was looking at. I've put my eyeballs in now and the first zebra does indeed look like a female. I think the large sized pictures threw me.
the first zebra has the fin and head shape of a female but can't give a 100% if you have a chance to photograph her in a few months and see if she has gained some size in her belly region then you would be sure, mature females tend to have more pronounced rounder mid section and when you look at them from the top they have an oval shape while the males have a more defined arrow head or diamond shape where the head region is wider as you can see in the last two photos.