Re: Too many interconnects
Personally I would use the cables you have assuming they are in good shape. If you are worried about the slight difference that may occur between types, try to match up the left front and right front cables. Use what you consider to be the better cables for the left front, right front and center channels as they will carry the majority of the soundstage. The surround channels are far less demanding and it sounds like the cables you have would be fine.
Subwoofer interconnects are usually longer and thus some people feel like they need to be larger than component interconnects as well as it is a single cable rather than pairs. They would also have the color code for the LFE channel. Other than that there is no technical difference from other interconnects. Many installations will use RG6 coax cable as well.