1) Well, the sun is millions of kilometers away, where as the lamp is inches away and focused in an enclosed volume. The heat produced is equivalent and in some cases greater.
2) I've got day and night lamps. The night lamp provides the heat while remaining unseen by the bp since its not in its visible spectrum.
3) Covering the insides of your hides in mulch or some type of insulator will work great and increase humidity levels.
4)Heres how I plan on increasing humidity levels, tell me what you think. I've got an old decorative fountain my moms throwin out with a working pump. So I plan on building a tiny waterfall thats about 10-12 inch's high which should increase humidity.
5) Lamp heats ground, ground heats snakes belly.