Hi. My kids don't have food allergies, but I hope you don't mind me answering the question anyway.
I would suggest, just don't take them to easter egg hunts. I know, it's hard to do that, but just avoiding the problem will make it so much better!
Or, another solution, is what I do every year for my kids anyway. I get the same number of eggs and fill them and hide them. Then I tell one child, "You search for the yellow eggs" and another "You search for the orange eggs". That way they will all get the exact same number of eggs. It's all fair! (And so not like real life!!! ha ha)
But anyway, you could have an easter egg hunt with your friends but put the appropriate kind of candy for your children in their eggs. Tell each of your kids what color egg they can hunt for, and if they eat what's inside you've already got that covered. And you can put whatever kind of candy in the other eggs for your friends' kids.
Good luck to you!