BBB, DS2 had multiple allergies and reacted badly to the foods i consumed going through my breastmilk. I was dairy/soy/egg/nut free breastfeeding originally. We started weaning using simple foods (you don't need to use a puree unless you are weaning at around 4months old; most of our 'weaning' rules are hangovers from when we were weaned earlier than we do now).
I basically used a 'baby led weaning' system, using very simple foods - ie plain roast chicken; pieces of veg, etc. He was a good eater and only refused certain foods. As we went along, it became clear he was also allergic to those foods he was refusing :-( there was only one food which he was additionally allergic to which he didn't refuse (wheat), however we had very little of it in his diet because as a general rule it came preprepared with other things that he couldnt' eat (and he had a healthy diet on what he was eating).
I made a lot of simple oat based snacks; fruit pieces, chicken pieces, etc. You DO have to watch to make sure other people don't give your baby food. There is a lot less you can buy over the counter, preprepared. However, as well as the above, we couldn't eat corn, legumes, gourds, peanutes, tree nuts ... but he's 4 now and he's always been very good at just accepting that other people can have stuff he can't. I've never made any bones about it. We cook things together, we find things he can eat; i try to make a cake for him regularly and freeze it in pieces so if we want something yummy for a birthday party etc, he can always take a piece along.
In the last year, we have managed to reintroduce corn (he'll eat popcorn, but not sweetcorn), wheat (he'll eat wheat, but he doesn't have the desire for it that most people do - he can give or take bread / cakes, etc, though he loves being able to have it if he wants it), and baked eggs. I tried scrambled eggs for the first time yesterday and he took the tiniest amount, said he didn't like it, but was happy that he could try it. Refuses legumes, though if i manage to hide a couple of peas, etc, he doesn't react.