Personally, I wouldn't hang anything shiny like tile or metal because when the sun hits that wall the glare could be blinding. Instead, I would want to soften it up with bamboo in planter boxes, of plants in the new wall containers: [houzz=]

A more decorative screen? Check out Front Porch, the catalog.

We retailed the fireplace in our bedroom. We had a similar tile to yours and wanted some more color. We ending up pulling the old tile and patching the cement to be ell and tiled and grout. I would imagine you could do the same

I would just put a black frame around the art you have there now (to match the frames on the other pictures) I would not put a mantle up but would wait until you have the fans out of the windows....that will make a tremendous difference. Then you can tell if you need a mantle or not