For me, i'd build out the fireplace with some simple white 1x trim and crown to knock down the mass of some of the brick- i love me some brick but that assembly looks huge! stick a nice piece of ever-so-trendy reclaimed wood mantle on there as well.
After that, stick with the white built-ins. just work the corner soffit right into it. wrap the upper shelving back wall sections in some white beadboard, and it would mostly disappear. you'd obviously lose out on a bit of storage, but as someone above said, put some little items, or framed pics, in that area, and poof, even more hidden.
hooray for MSPaint!
Q
Nice fireplace remodel - more like ours
Q