Okay I have of course been following Coops story and I think it's time to do the one thing you have not tried.
Get him off that crap of food!!!! At this point, it certainly would not hurt him since he is throwing up what you give him already.
All of his symptoms are allergy related. (entropion is the rolling inward of the eye which can many times be caused by swollen eyes from allergies, interdigital cysts are formed from bacteria build up, from either paw licking or immune system not producing good bacteria, tear stains, runny eyes.... )
His immune system is going downhill, which is why he is getting worse, and showing more and more signs that it is taking a toll on him.
First, you must answer the question: "What causes allergies?" Why do some years you have horrible allergies and others they are mild? You may assume that there is less pollen count or something, but it actually has to do with your immune system. Your immune system produces antibodies that combat allergens.
So if you are in top shape health wise, diet and exercise are good, you will have less allergy symptoms that normal. But if you have a virus, infection, are pregnant, eat nothing but McDonalds everyday, not on a good diet and getting regular exercise, ect. your allergies will be horrible!
One of the reasons food change helps so many bulldogs is because a good diet can help build up the immune system and help produce antibodies to fight allergens. While it does not cure an allergy, it will certainly make it less uncomfortable than normal.
So at this point, I know you wanted to wait until the tummy settled to try a new food-- but if you really do not think he swallowed something large and has a blockage then I think it would not hurt to at least try a new food.
However, I do think getting a scope would be beneficial as well. But if he is pooping normal (2x a day) if it were me, I would try a food change first. Or try bland diet instead of the prescription junk.
I cannot be sure but I am thinking that @
kazzy220 's Maggie used to throw up all the time until a fromm switch. She also had interdigital cysts when trying a new food that disappeared when changed. If it was not Maggie, maybe someone here can remember the dog that threw up every night in the middle of the night?
While it does not work for everyone, I do think it is worth a try at this point. HUGS xxoo