POWERBRIDGEONE-CK Single Outlet for TV and Sound-Bar Recessed In-Wall Cable Management System Kit (ONESB-CK)

Is it paintable? My Bose 300 is about 2 1/4 high and the soundbar piece may show slightly. I want to camouflage as much as possible.

How long are the power cords between each plate?

Is it possible to use my own romex to extend the reach of the power supply from a wall without outlets to a wall with outlets? I need about 50' extra

I have a samsung hw j250 with a brick ac/dc cable, is there any solution to hide these wires along with the flat screen tv cables?