EB while not your friend is something that invariably shows up. Spraying with whatever you're comfortable spraying to protect the new leaves, picking off the affected ones, keeping the leaves as dry as possible, thinning for air flow maybe, is about all you can do. I've never had it kill a plant outright and at worst I've had to throw some shade cloth over tomatoes to prevent sunburn because of the loss of leaves. I've lost plants to Septoria, though, and we don't even want to mention LB.
The thought of losing so many tomatoes is scary indeed.
I've never tried Iznik before and I've only tried Zephyr and Butterstick from the squashes you listed. Are any of them regrows for you or are you trialing the rest this year? It's easy to go crazy when you are looking at seeds in stores, catalogs, etc. and dreaming of the perfect garden.
