Here's my two cents. Don't do it.
Now, take into account this is from a provider who has done it. At first it seemed like no big deal. And, for the most part it wasn't. BUT, then I had another kid in care who had a REAL (as in medically necessary and not a life choice like being vegan) dietary issue. Now I had TWO kids in care with "special" diets. Try making lunch for five kids and two of them have to be completely different from the rest. It turns into a LOT of work.
And, it is a lot of work from the perspective of impromptu things....so, you make a quick decision, on a beautiful day to head off to the park. Now you have to quickly think of special snack options. Or, when you have a party. Well, if the kid is vegan then cake is out. So is icing (icing sugar involved bone fragments in the production process). Unless you are an exceptional baker and know how to bake vegan style no special treats for that kid.
It seems easy at first but when you are actually in the throws of it you realize just how many things are off limits. For example, at Christmas we made gingerbread houses. I even bought vegan graham crackers. We did up all the houses, were so proud and then vegan mom is a bit upset and reminds me that the smarties on the house have chocolate in them.Ack, stupid me.