Glad this one got their safely. He's a great looking GU!
Your hide should be on the cooler side, when he wants to heat up - it's basking time. If you can swing it, mid to upper 70s would be a good hide temp. Offering deep enough and plenty of substrate is the easiest way to let him thermoregulate. Then he can dig down as close or far from the heat source as suits him. It's also a good idea to have some damp sphagnum or orchard moss in the box hide to help with sheds.
Depends on the tegu. Ask the previous owner what his favorites were and you'll probably have him gorging as soon as you can fill a plate. I feed as much as they'll eat daily until they get close to max size. If they hibernate well this usually happens around year two.