Yes, you need two thermostats if you have two UTHs. Those stats are a good 'for now' stat while you save up for the better ones. I had 5 (sold 4, so now only have 1) that worked great for over a year with no issues. Others have used them for only a week and they've gone haywire. You just have to be careful setting things up and keep an eye on them.

With 2 UTHs, you really shouldn't need the lamp anymore. But if you do, be sure to have it at least 8" above the screen top so it doesn't sap the humidity.