Nothing wrong with the 6EXAS. Nope, the Hitec you found is not a computer model. The quickest way to tell is to look for the little screen somewhere on the front.

The issue with voltage cutoff is that if you discharge Lipo batteries too low you will damage them. Most ESCs have a cutoff that turns off the power to the motor when the battery reaches a certain level. The power to the BEC is maintained. This gives you a clue that it's time to land. The cutoff point for Lipos is different from other batteries, so you want to be sure that your ESC has a cutoff for the Lipos. Some ESCs actually have a programmable cutoff point.

Yes, NiMH and Lipo packs do not need to be cycled. However, I do occasionally cycle my NiMH packs to be sure they still hold the right capacity.

I'd have to look at the charge capacity of the MKII again. If you're going with huge Lipo packs, you're going to need something more capable.

Many people refer to the Duraplanes as Durabricks because they are so heavy. When I bought my first kit (Sig Scamp) my instructor drilled it into my head that planes should be built to fly, not to survive crashes. He insisted that I keep the construction light. Building survivable planes is kind of a self-fulfilling prophecy. They're heavier so they need to fly faster and then they're more likely to crash.