HI mothernature. I just typed a long message and then my pc crashed. but to summarise my own post:
I have used probiotics since ds was 7 months and just empty the powder from a tablet into some pear puree. I do this twice a day and I can tell if I need to up the dose because we get a revolting poo. Pre mixed ones tend to be in a dairy base - so be careful.
My ds is now almost a year and still avoids, nuts, dairy, eggs, wheat and gluten, added sugar, artificial anything, preservatives, citrus, kiwi fruit and tomatoes. It's a pain but its worth it to know one day he will be able to eat most of these things. At the moment I can limit what he eats (and I am sure he would happily eat sweet potato, lamb and pear forever), once he starts school I won't have the same control, so its a small pain now for a large gain later IMO. I cringe when I see a 6 month old being handed a biscuit, and I'm glad I've got an excuse for being a strict mother when it comes to diet.
IN terms of the bread thing. Well, most bread has soy in it, which I would be more concerned about given your dd's allergy. It could even have contained milk. I'm not saying this to worry you - after all he didn't have a reaction, but it would be a good starting point to explain to people why you are limiting his food.
I have used stickers in people's pantries to show what they can and can't give my ds. Red for no and green for yes. My MIL still can't get her head around the fact that margarine contains milk, so you have my sympathy.