I'd do mini bagels with cream cheese over the croissants/ pastries, that's lots of sweet stuff on your list. It doesn't matter if you hate them untoasted! Most kids love them.
Or maybe do a tray of cut veggies & pita chips along with hummus, or chips with salsa/ guacamole.

How many people are you having? We went to a 10 a.m. party that had bagels, fruit kabobs, coffee and then cake. It was fine.

My only critique is that while a little yogurt bar sounds cute, it's easier to eat things that don't require assembly and a spoon, outside. Also, you might not like untoasted bagels, but I'd probably have at least some mini bagels because kids (and some adults) do like them. I would also add something with protein besides yogurt--cubes of cheese maybe?

We are having a party for our son outside at a covered park shelter at 10am.
Here is what I am planning to serve. What would you add or change?

Iced coffee
Juice boxes
Horizon milk boxes
Water
Liquid sweetener for coffee

Assorted croissants and pastries (I was going to do bagels, but I hate untoasted bagels)
Gluten/dairy free apple spice muffins for allergy kids
Blueberry muffins by request of birthday boy

Plain and vanilla yogurt
Mixed berries
Mango cubes (birthday boy's request)
Variety of granolas
Cups and spoons to make parfaits

Cupcakes to eat or take home