The ICC is not necessary at all for your application unless you plan to expand past 15 zones. The ICC is built for large commerical applications. The Pro-C is a fine choice both in affordability as well as reliability. As for the backflow, like Toxin said, you will want to make sure one is installed, required or not, it would be a very wise and inexpensive investment to make to protect your water supply. Not sure that a back pressure device is necessary, but a backflow device is highly suggested.
Tony Posey
Ridge Run Landscapes