If you put the plastic bin on a table or something with legs, a little raid on the legs will keep the ants out of your crickets. You may have to do it a couple times a year though. I have to do that with my BSF set-up.
Just my opinion, but I'd think that as long as they had cover from the sun they'd be fine. So as long as there is plenty of vegetation and access to water like all chameleons I would think they could "feel the burn" (insert lame gym joke here) and hang out in the shade if the sun was burning them.
Not sure if they make the coated hardware cloth in sizes smaller than 1/2 but if so that would be even better. You could always cover part of the top to provide some shelter from the elements.
Look into 1/4 or 1/8 hardware cloth. 1/8 is harder to find but would be my choice. You could use it for the top and bottom if draining where the enclosure sits isn't a problem. You could also use composite decking boards for the bottom but wet dead insects could still pose a bacteria problem.
Let us know how it goes. I plan to get a colony started in South Florida in a week or so that will also be stored in a shed. I'll probably try no substrate first and see how that goes. North Florida doesn't have as much of the afternoon thunderstorms as South Florida from my experience so mold...
Natural sunlight is great for them but they should still be in an enclosure of some sort. Never know when a bird or stray cat will make an attempt to grab a chameleon lunch.
I realize the overwhelming consensus is to not feed wild caught insects, however veiled chameleons (and other chameleons) wouldn't be thriving in various parts of South Florida if wild insects weren't relatively safe and provide much of the nutrition necessary for a chameleon to thrive on. I...