I can understand your problem with stress factor - we're going through the same thing with Missy. It appeared at one point that we might have to part with her. However, in the past couple of weeks, it appears that she might be coming out of it. At least she seems to be more back to her normal old self. We go through some sort of "ritual" with her about twice a year with runny stools and occasional vomiting.
We have since put it down to the poultry protein in the kibbles that are/were causing a lot of the issues. We used to give her the odd kibble meal, and it's really a no-no with her. She has been mainly on raw food all her life since we started having issues with her at the tender age of about one year.
There is a food product on the market that can be picked up at the vet's and at some pet food suppliers that is Hypoallergenic which our vet strongly suggested I put Missy on. From what I understand they have done something to the product that masks the proteins or carbohydrates that are causing the problems with the animals.
I personally did not do this due to the fact that I had discussions with other veterinarian people over the years and one of their main concerns was adverse reactions to poultry protein. And years ago Missy literally refused to eat chicken and I switched her to lamb, beef, and pork. And a year ago I went back to making a turkey meal and the problem flared up again last August.
Also, we're in the same boat as you are. We are at least 8 or 9 hours away from the nearest vet university at Guelph, Ontario. We are not aware of any other facilities in Ontario.
From what I understand, food intolerance can be more of an internal problem re diarhea, throwups, bloody stools, and so on. Allergies are more apt to rear their ugly heads as a skin problem of some sort - severe itching, licking at their paws, severe head shaking possibly from ear infections - just to name a few.
I think under certain circumstances that an animal could have symptoms of either one or both at the same time.
One other thing that you might want to look into which will help the stomach issue and the diarhea, is Slippery Elm Bark powder. Pick up a bit of it in bulk at a health food store and make up a slurry. This may help with the stomach issue. It did with Missy.
She is now back strictly on raw food - no kibble at all - and absolutely no poultry protein.
Animals are such agreeable Friends.
They ask no Questions. They pass no Criticisms.