Don't mistake a thermometer for a thermostat. They are both necessary for a proper and safe enclosure, however the unit on your list is a thermoMETER.
A thermoSTAT (Herpstat, Helix, Ranco, Hydrofarm, etc.) controls the amount of energy emitted by your UTH. Without this, your snake can be exposed to temps upwards of 130F, which are far too hot for any snake species. The thermostat should be the highest quality aspect of your setup, and the best you can afford. Herpstats are regarded as the golden standard around here.
As for everything else, you're on the right track. Most people will say to steer clear of sand as substrate and opt for aspen, cypress, or even plain newspaper/paper towel if you're okay with forgoing aesthetics. You can also skip the UVB bulb and cage carpet for under substrate.