Haven't done my JK (YET), but I did this to my DJ..
1. The front floor boards have a rough surface to them - is that something to take a grinder to, or do folks just herculine right over it?
DO NOT grind that off! it's dampening material to keep your pans from "bonging" like an empty jerry can
I'm not sure what you could do about the ugliness of it... maybe run a few extra coats and try to level it off with the herc some...
2. Any tips for removing the rear seat belts?
big *** cheater bar?
3. The cover for the rear storage is covered in carpet - it *looks* like it is glued to the door that covers the well. I have seen a bunch of pics of herculined jeeps. So does that rug come off or are people cobbling up a replacement door out of sheet metal?
That thing feels really cheap to me... I'll probably replace it with diamond plate (cause I love aluminum diamond plate)
On my DJ I just poured it straight from the can and rolled it out... it made it go pretty easy and fast
the more you keep rolling over it, the more texture you get.