Your first problem is relatively easy to solve. As others have said, just feed them separately. I had two dogs once whom I had to separate. One would finish more quickly than the other and would go to the other one's bowl. That dog would let out a little growl and, although there were no fights, I wasn't taking a chance. One ate in the kitchen and one ate in the bathroom.

Regarding the nipping, etc. I would encourage you to take Buck to obedience school. It really is not very expensive at all and you will enjoy your dogs so much more. Ask your vet for a recommendation for a good school. Oh and yes, Buck needs to be neutered!