For the misting, I have heard about the magnify glass effect (some people say it makes no difference). I think with the smaller particles it would be much less of a problem. Especially since the water droplets would evaporate pretty fast. What I do to increase humidity passively, is place water saucers in between the plants making sure the water gets ample sun light. When I hand water the plants the excess water falls into the saucers and evaporates during the day.
I find that surrounding the arid sensitive trees, up against larger leafy trees seems to help a lot. My larger pomegranate trees produce nice micro climates for the other plants such as the kiwi vines, dragon fruit, and lychees.
Kiwi vines like the water and are heavy drinkers during the hotter days of summer. I found the SWC container provided a huge benefit to the kiwi during summer. The lychee also has very little sunburn/heat stress in the SWC. I originally thought that the lack of humidity would never give me healthy sub tropical trees. However there seems to be only certain trees which can't adapt to arid conditions (Theobroma sp. seems to be one of those that can't adapt for me).