-I wondered about number 1 myself. If the MRT comes loose, then you've just got a regular nut.
-My gut tells me that if your torque target requires that you stop tightening in the apex of the lobe, then it'll lose preload until the tine falls into the previous valley. This means that on any tightening cycle, you'll have only discreet preloads available to you
-From what I've read, a tool is required to remove the nut. There is no special tool needed for installation. No clue on if they're reusable or not.
-Don't know about #4 or #5
To me it seems like an interesting idea, but I didn't see any technical resources or test documents, just their white paper and brochures. It's why I wanted to see you guys poke holes in the idea. So far, that whole "How does the MRT affix to the nut" seems to be the most important question.
On the other hand, the Navy is testing these things to replace other fastening systems used to affix the skirts to their hydroplanes, so they're getting some pretty intense real-world vibrational testing right there.