Just like people all fish genetics are a little different. Some angels are little smaller. My veil tails tend to be smaller bodied. If he is getting enough food(sounds like it) and water parameters are good (sounds like it) I would just enjoy him and not worry.
When angelfish are first forming their fins their water has to be absolutely perfect. Any ammonia, Nitrites or Nitrates at all can cause their fins to be twisted or less than perfect in some way. After those fins are formed theres no way to straighten them back out. thats why when I have angel fry they get a bare bottom tank with 50% water changes every day for two months (Yes it's a lot of work but worth it)
Now as for your zebra veil when he was a baby(unless you raised him and you know better) he probably had less than optimal water conditions.
Those are pectoral fins by the way

Carol