I am suspecting that the heat is the main culprit.

The bugs are there for the manure smell, I think, and shouldn't cause plant death as far as I know.

I wonder if the manure is too "hot"-- too much nitrogen "burning" the plants? How fresh/composted are they? 50% seems a lot.

Also, are you saying the bed is 1 foot by 11 foot? If so, seems like way too many plants for a small area. Enough space for everything?

Rig temporary shade.

You may have better luck in your second year. I'm a big advocate of planting over grass, as it will compost down and create rich soil. But it's always best to give it several months to decompose before planting. I probably would have gone 2' wide at a minimum, though I don't know how much the narrow width will hinder your garden.

I'm in agreement that your wilting is most likely heat. That temp is awfully hot for new plants. If they're turning yellow and wilting, they're getting too much water. If they're staying green and wilting, they're not getting enough water. I always give my plants extra water when the temps go over 90 like they have this week.