If you are going to drive it on the street dont buy anything but a mesiere pump. The CSI's overheat too easily. As for the belt setup, they make just about anysize serpentine belt you can possibly think of. FOr the last customer truck we bought a 59.5", 60", 60.5", and a 61" 6 rib belt. We determined the proximity size by wrapping a clothing alteration style tape measure around the pulleys. FInd the one that fit the best and returned the others.
As for removing the assecory brackets it all depends what you want to use. If you are going to run poswersteering then keep the DS bracket. If no maybe a low mount March kit for the alt?
The idler pulley will have to be fabricated wherever you need it. Like I mentioned earlier, we can build that for you.