Kitty recovering from pancreatitis/ possible mild IBD and food allergies- food recommendations?

I'm new here but have been lurking for awhile. I need some advice from people who have experience with my kitty Sam's issues.

Background: Sam is 11 and just now almost fully recovered from pancreatitis caused by getting into some dry food samples given to us at a pet store. He ate almost the entire small sample bag of Fromm's chicken a la veg dry food. Vet says this is what caused his pancreatitis due to the extensive list of ingredients including tons of fruits and veggies, which he NEVER consumes. Normal food before the pancreatitis was Purina Pro Plan indoor care dry out all day and half a can do Friskies wet every day. I know he has food allergies, as he picks at his skin until it scabs and licks till he's bare. This is a secondary condition to the pancreatitis, and I also have suspected Mild IBD for awhile due to bouts of diarrhea once in awhile.

My question: I want to start mainly feeding him only wet food, but would like a good dry food to give him in the event I will be gone from the house and cannot get him his wet food right away. Right now until the end of next week, vet has him on the Royal Canin GI High Energy prescription wet food. He said I could also do the Hills w/d. Sam likes both a lot, so during the recovery process, not a big deal.

So..... Once he is done with the prescrip food, I am wanting to lower his chances of food allergies but also another pancreatitis attack. I am looking at Natural Balance Limited Ingredients wet and dry food both (the wet would be what he primarily gets). My biggest concern is the pea added..... I know that was one of the ingredients (among a trillion others) in the FROMM food that set him off. It would seem more likely to me that the grains and corn were what were causing issues in the Pro Plan dry food but its so hard to tell. What do you guys think? I want him as healthy and happy as possible...... Oh and also, since going on wet food only since his pancreatitis attack, he is definitely scratching less and his eyes have no discharge as they did before. I know a raw diet will be suggested, I think it's a great thing but not something I'm wanting to tackle at the moment along with everything else. Any advice for me and my Sam?

Also wanted to add... The vet saw no issues with going bad to his normal food regime after he fully recovers from the pancreatitis. I thought this was odd as I know a low fat diet is important to prevent a recurrence.... I brought this up to him and he said they have found that is more the case for dogs and not as pertinent with cats. And like I said, the food allergies are secondary, and discussed briefly with his doctor, but I was really only left with the advice to try different food until I find something that doesn't make him react. Sigh.

The usual way of finding what is causing an allergic reaction is with a food trial.  The cat is fed a food with a novel protein and carbohydrate that they haven't eaten before.  The cat is fed only this food for 12 weeks, no other food including treats.  I know Natural Balance does make some foods with novel proteins like rabbit and venison.  Of course the allergy may not be caused by a meat protein.  Limited ingredient food is the best for a food trial simply because it limits the possibility of an allergen.  A food allergy could have caused inflammation that produced the IBD type symptoms.

Ok... I think the natural balance would be a good choice then... Just worried about the pea possibly causing some issue and possible re-flare up of the pancreatitis. :/ apparently I am a very paranoid furmommy!