That's a big drop cloth that I used to help seal out the bottom from the wind and insulate the pot a little more.That form fitting greenhouse bag is impressive. Controlling the temperature must be challenging with the fluctuations you get. Also, making sure the tree doesn't cook if the sun hits it. Are those wet towels for humidity in the bottom?
I may just get bold enough to do an similar setup with a large tropical bonsai here in Pennsylvania.
I cut it back about a week ago. I don't defoliate the guava. I see no need for it. I trim to shape it and this time was a big cut back.When did you defoliated? I also have a strawberry guava, is it still ok to defoliated now?