Q3 -- Check the pic, theres 2 pairs of output, Front and rear, and one for the subs, subs aren't read outputs .. I'm looking into that deck also..

Check this link , it has pics of all angles, front rear or player and for most HU too..

sorry, my broswer has loading issues (on campus) so heres the link, Just search for your DEH-P6800MP @ www.sonicelectronix.com

and check out the pics.. ! even shows the all the display backgrounds