There is a fantastic selection of gluten free easter eggs here which in many cases are also dairy and soya free. Remember most (but not all) people are fine with Soya Lecithin, it is a very highly purified oil and contains none of the protein to which most people react adversely.
Dairy free easter eggs re much easier to find than in past years, and children like the "Moo Free"
Many of the Hotel Chocolat chocolate is "free from", all are gluten free as far as I know (do check!) and all vegan ones are dairy free. Narrow your search and there is something for most people.