We didn't use any egg substitute, just didn't give him anything with egg in it! Luckily he was never very interested in cakes etc until recently anyway
so it really hasn't been a problem. We did make him an egg free cake for his 2nd birthday which was "interesting" but I don't think he even tried it, mummy was forced to eat most of it
.
I did look for egg substitute but could only get it via the internet so didn't bother! If you google you should be able to find info on what words to look out for in ingredient lists when you are shopping. Luckily in the UK most packaging states what allergens are in the food so it was easier to spot. Visiting friends/family was harder and buying food from bakeries where they often use egg to glaze products.
We were lucky that like you his breathing was never affected and he had no swelling in his mouth. But allergies can get worse the more often they are exposed so avoidance is the best idea. I would see your Dr so they can keep an eye on him and arrange testing/ a challenge when he is a bit bigger so you know where you stand. From what I have read, most children have grown out of egg allergies by 5/6 years old.
The pancakes sound good!
Laura