Yes, a dog can get an angry pancreas even if they have had normal bloodwork all along. You can't really tell which dogs are at risk for the most part, so if there is a predisposition in the breed, it's all the more reason to be careful.
But with that said, I don't think there is a reason to live in panic thinking that it will happen. Even if it's a common Yorkie issue, still most Yorkies are not affected.
IMO:
Feed a good food and involve a vet or veterinary nutritionist in the decision.
Be careful with fat and maybe even protein intake.
Give treats in moderation and nothing high fat.
Avoid overly rich human foods. If they never get it, then they don't know what they are missing (and I suspect they are just as happy with a tiny piece of lean chicken or the like anyway).
Don't give over 10% of daily food intake as treats or chews as a general rule. Overtime, you run the risk of unbalancing the diet.
And if they get pancreatitis after doing that, then there is not a darn thing you could have done to stop it.
Bottom line is to think about everything that goes in their mouths (within reason). Enjoy your pups. The ydon't want you worrying about their pancreases too much.