Our wonderful neighbor is helping us re-do our fireplace, and we're ready to choose colors and such. Here's where it stands now. The walls in our house are a color called "wood ash" (seen toward the window, although it doesn't look nearly that dark in person), and then the blue seen to the left is an accent color. The two narrow slits to the side will be slide-in shelves that are being built separately, so just imagine them for the moment

The large box on top will have doors and house our TV. Underneath, you see the gas fireplace.

Okay, my questions:

1) DH really loves tile. I'm not super partial to it, but trying to indulge. We have chosen kind of a slate color that will go on the bench, and then a little around the gas fireplace itself. My problem is that that second piece that's directly below the TV cut-out creates a small space maybe 2 inches set back. So where do we stop the tile up the side that isn't awkward? (One thing DH suggested is creating a small shelf at the top of the part that's sunken back with the fireplace, and I'm liking that idea, but would love other suggestions).

2) What color would you paint it? We're leaning toward white--we have all our trim painted white, as well as the window seat to the right in the photo. We're open to adding some more color, but can't figure out what would go.

3) We're planning to put two side mantels on either side of the TV (We would have loved to be able to sink the TV back, but that wasn't physically possible. We're kind of stuck with the physical lay-out here.) Is that what you would do? Any other suggestions? When the TV doors are open, they'll open back against anything we put there, so it can only go out flush with the TV box.

I don't know if that made any sense. Kudos if you figured out what I was trying to ask.
(I included the mirror photo just for a better idea of the "wood ash" color).