The Jandd rack came with brackets that were already the right shape and are adjustable as to length and also IIRC the "splay" on them is adjustable too. I had zero problems mounting it. I don't recall having to bend anything.
Yes! Before I knew that those brakes are pretty powerful I went to a friend of mine who does a lot of motorcycle work out of his garage and sliced off the mounts down there and he welded on new posts on the rear triangle. It's nice having the clearance down there too, I don't do a whole lot of trail riding, but every now and then I do, and if you have to scrape over a log or something not having the brake right there is good. Some people will tell you that if that brake is dialed in it is quite strong though. Mine wasn't working well when I got the bike so I didn't get a chance to try it out properly.
A quick google image search for "Jannd rack hardware" turned up this:
http://www.bikebagshop.com/jandd-ext..._7c11681678102
I don't recall exactly how these mounted (there is directions online somewhere though), but be aware that they mount so that you get the splay you need if used on another rack. If you have a drill and the other rack has a deck (not tubular) you could tap it.