It should work for the rear wheels, now the front wheels may be a diffrent story, I am now too familiar with the brute's wheel sizes, but I know that I had problems putting a 10" wide tire on the front of my rancher.
Yes, that should work just fine. Not to sure if the tire will clear the inside of the machine though. Just take a look at how much room you have between the inside of the tire and any parts of the machine, just to make sure the tire won't be rubbing on anything.