A:AnswerNot much harder. I'd recommend using an electrician's fish tape instead of the included fish sticks. Just be careful to not hook the insulation when you pull cables back through the wall.
A:AnswerI had to wrap the cable around the mounting bracket for the soundbar and back to the power connection. I then used a cable zip tie to do the rest.
A:AnswerYou can't really remove the wires to the sockets (at least not at first glance). I guess you could just leave the second socket dangle in the wall. Or you could just run the wire to the upper socket and never use it. I think I see why you want this kit - you want to run AV cables all the way to the top and down to the speaker.