#2. If you're running rca plugs from your head unit to the amp, run the speaker wire for the front speakers in the same area, yes you will need to use speaker wire. The amount of speaker wire you end up using will ultimately depend on where you mount your amp.

Bridging, check your amp user manual to see if it's even bridgable. What Amp and Sub are you running? Also, you may want to check your amp to see if there's a built in crossover or lowpass filter, if not you're going to have all the regular frequencies going to your sub as your front speakers, which isn't the greatest for sound quality. As well a general rule is that your sub has double the power of the speakers in your system to get the best results. (I might be stating the obvious....)

Hope this helps.....