Diversity works best when the antennas are separated by at least one wavelength. More is better. The radome isn't big enough. Same with MIMO unless they're using polarization diversity.
Sorry, but I don't see that.
I don't think so. Carbon fiber makes a great RF absorber. Find some CF and put it in your microwave oven. Here's a preview:
That's easy. It's a sloppy installation. I don't see a rams head on the top pipe, or any manner of water protection on the lower pipe. Water will just slither down the coax cables, into the pipe, and fill it full of water.