I think the original question was answered, but the two small white spines on the back are normal in my experience. My porcupine is seems to have lost them with age, but I always check out youngsters at the store when i see them and it appears common.
For feeding, mine will go nuts for a few live Rosie Reds, gets him alot of exercise while chasing them and trying to beat the lion and trigger to them. I usually feed fresh shrimp soaked in Zoe, both of my puffers would rather eat that than anything else. My porcupine will occasionally take a silverside, but only if he thinks the lion is about to eat it.