Hey Ryan, you have too many PMs and I am unable to reply to yours right now.
Here is what I wanted to say:
OK, in answer to your most basic question, "Is is it possible to use these controllers off the 110V line I have at my disposal in the way I want to?" The answer would be "no". You will have to supply them 230VAC to power them up.
Also, a 2kW element at 110VAC draws 18.2A. Your controller's contacts are rated at 16A, so you would also have to have an SSR to handle the power to the heater.
I am about to leave for the evening, but I will try to redraw the diagram in the morning if you want and see if I can provide a better explanation.