Talk

Sounds fine, to be honest at a lot of parties the food gets largely ignored anyway.
Keep it basic and it should be fine

Sandwiches were always overlooked at my DCs ' parties. Squares of basic home made pizza went down well. The rest of your menu sounds ideal.
Suggest you ask the Mums of the allergic children for more details - nut allergy covers a broad range and you need to know if your house needs to be nut free or if it is only a problem if the child eats nuts.

Not the cheapest way to do it but the simplest IME:
buy food boxes example

Then make up a round of sandwiches, in a bag, a mini bag of apples/grapes from the supermarket, a few cocktail sausages, a bag of crisps from a multipack and a drink for each child. You can make veggie/food allergy ones separately and name them so less chance of cross contamination. I used to make the round of sandwiches four quarters of different things, so every child got at least a couple they liked.
You can put extras in the box (hooter, streamer, balloon, little toy etc) and then they can take it home instead of a party bag when you slip some cake in as they leave...

oh, and cherry tomatoes: they've always gone down well.