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!).
Wellcome to the forum.
Your second zebra is a MALE for sure. Excellent pictures of your second zebra.
The first picture is a little blurred/out of focus so it is a little difficult to tell.
The cheek odontodes or bristles look a lot smaller than in your other zebra, but this may be due to the picture quality. If this is true than, it is a female.
Your 1st and 3rd look like females.
Your second one is a male.
Your 1st female (last couple of pictures) looks "pinched" behind the pectoral fins which is not normal. Either its needs extra food or is infected with worms which might be taking away the nourishment.
it's good to hear about the females, but not the last.
I don't think she have worms. I think i have to feed some more bloodworms. maybe the other fishes take it first.