The carpet is fine, but newspaper or another sort of disposable substrate (or alternatively, a loose substrate like aspen or cypress which you can spot clean) would be much easier for you to clean. That's up to you of course - just a suggestion.

Make sure that you get a thermostat to regulate the under take heater and keep your snake safe from extreme temperatures. He will be fine without a light

Lookin' good so far! Congrats on your new addition, welcome to the site!