Habistat is just a brand of thermostat (Microclimate is another) - it's used to keep temperatures stable in the tank so it doesn't get too hot or too cold, you can get ones designed to use for mats, lights and ceramics. Dimming thermostat is best for lights as on/off thermostats will kill your bulb (and are plain annoying switching it on and off!). You can also get pulse (mostly for ceramics) and mat stats (for heat mats).
A lot of people use play sand - it's cheaper and doesn't encourage your animals to eat it like calci-sand does. You just give it a rinse, let it dry then pop it in. There are other substrates too, some use slate, lino and I've seen people use excavator clay.
Yep those are timers, just set it to the times you want and it'll do it all for you.
Never heard of that one. Not saying they're wrong but don't just go with the advice of one pet shop, have a search around and ask other people as husbandry differs between keepers.