Would monitors attached to my USB hub make my CPU run hotter?
I found the answer:

USB graphics devices, like the USB-HDMI-DVI, are “virtual” devices where much of the heavy lifting is done by the CPU, by hooking into the graphics stack. 

Even so, I'll keep this set-up and monitor things with iStat. All I display is MSFT Word documents and stupid web pages. I think I'll be ok?

Sorry I did not do more research!