Even if it was food safe, I don't want food that has been in a hot car for multiple hours.

Make sandwiches and fruit and put them in a cooler.

For picnics where the food will be left out for a while and/or in the heat, I always make some of the following:
- Texas caviar-type of bean salad
- Cabbage slaw with a sweet/sour cider vinegar dressing
- a greek-type of "ladero" type of vegetable dish. Either eggplant or zuchhini stewed or roasted in tomato sauce. This is delicious served at room temperature with hearty bread and/or feta.

I generally steer clear of anything with meat, eggs, mayo, or dairy on hot days.

As others have noted, the solution to your problem is to make whatever you want and…put it in a cooler.

I’d pack PB&J and just J sandwiches, along with chips and lots and lots of fruit. I’d still bring in a cooler with ice packs.

Can't you go with "cold" type foods? Sandwich tray from Wegmans, cucumbers, watermelon, chips, goldfish.

Nobody, especially kids, want quiche or potato salad after playing for 2 hrs in the heat.

And they are egg abd mayo based, respectively. Do you want people to get sick?

Lemon Basil Pasta Salad

Serves 6 to 8

1 pound mini penne or farfalle pasta
4 plum tomatoes, diced
20-30 basil leaves, cut into chiffonade
Juice and zest of 1-2 lemons
2 T extra virgin olive oil
2 T rice vinegar
Fontina cheese, cubed, to taste
Kosher salt and freshly ground pepper to taste
1/4 cup grated parmesan cheese (optional)
A few shakes of red pepper flakes (optional)
1-2 cloves of garlic, crushed (optional)

Cook pasta according to directions on box, drain and rinse with cold water until pasta is cool. Toss pasta in a large bowl with all other ingredients.