Hi, one of mine has pancreatitis. She was initially fed on tinned Chappie when she came home from the vets, but after about a month I swapped her onto Natural Instincts Special Diet which is a low fat raw mix and now she is on Nutriment Low Purine raw mix, again low fat.
Treats - She loves carrot, so gets carrot a lot and also Antos chew sticks which are also low in fat. Training treats are boiled chicken breast chopped up ( keep an eye on reduced chicken breast in the supermarkets), Barker and Barker vegetable training treats or Antos training treats.
I spent a lot of time looking at the nutritional analysis on food and training treat packets, it is a bit of a minefield, so many foods and treats are high fat to make them more palatable.
Hi, our JRT has had issues with her pancreatitis for so long that now literally the only thing she can eat without getting seriously ill is the Hill's I/D prescription food or plain boiled chicken/brown rice.
Hopefully yours is nowhere near as bad, but in terms of treats she is absolutely fine with the stag bars and she also copes with bits of unsalted, unflavored rice cakes.
As I said though she is a particularly bad case, the vets have always recommended the tinned Chappie as a good alternative to the prescription food.
As Teaselmeg said you will learn to be an expert on the fat content of foods!