The hoop structures are great! I'd bet that the shade cloth would keep out the rain, at least if they doubled it. Reminds me of my old trampoline arc coop--using the frame of the trampoline to make 2 half-circles, 6 ft apart, with fencing etc, all covered in shade cloth.
I have the shade cloth covering the end of my chicken coop that the top is covered in wire where I run the mister's at when the heat rises. My shade cloth is only a single layer though, and this is going on the 6th year that it's been up there now. I do have an extra spare one for whenever that one wear's out beyond further use, as I bought 2 of them back then. A single layered one will not keep out the rain, but the mister's create wet ground anyway's when you have them on.