(1) I don't have the exact wire color, but you could grab it from behind the dash...but the best way is to go into the engine bay
(2) I ran my power wire through the main grommet that all the wires pass through right above the fuse box in the passenger compartment... That way you don't have to drill any holes, and you could seal any unwanted air holes with caulking.
(3) Yes, like stated above, directly below and a little to the right of the battery, there is the main grommet, with a bunch of wires loomed together.
(4) I went to the auxillary power terminal (the one you don't have to reach down into the engine bay for) to get my power. It's by the fuse box in the enigine bay....you could reach down and tap onto the battery itself, but it doesn't matter, cause they are shared power sources. The one by the fuse box doesn't need an adapter, the one and the battery might.