Veterinary Technician is what I originally went to school for
, was Vet Tech for the Zoo for a couple years, but then decided I liked Zookeeping better (felt like a more personal relationship with the animals).
Yes, people do use non-food rewards for training, but in my experience it is much more challenging to train a "non-food motivated" animal. It absolutely CAN be done, but for a first attempt at training you might do well to consult with a professional trainer (puppy classes or something), especially since your pup also has some aggression/fear issues, which are pretty serious problems that usually worsen if not dealt with when the pup is young. A trainer could give you a lot of guidance & techniques specifically for YOUR dog.
Another thought as far as rewards go... what about loading something liquid into a syringe (no needle!!!!) or squeeze bottle and letting him lick/have a taste of it as a reward? Chicken or turkey baby food is a healthy option that I have used before. Carrots would be fine, but again, if he takes forever to sniff, pick them up, play around, chew, etc., etc., it will really slow down the training process. That's why I was thinking of something that he could have a quick lick/taste, & keep going with the training session.
PS: Don't know trainers in your area.. A lot of our larger "Pet Supplies" stores offer puppy classes, I know your dog is a little older, but you could call & ask. Or maybe call some local groomers, they may know of someone.