What about mosaic tile? Lots of colors, styles, sizes, and finishes to choose from. You can also mix tiles or keep it simple and uniform - whatever you prefer! This fireplace was done in a single color of iridescent tiles, very sleek and modern! (other colors available!)

I love your outside entertaining area. It does need a color that would complement but give the area a focal point. I like the darker red,orange colors you may find in natural. You could dress up the table with accessories and place cushions in a complimentary color on the benches. Colored potting containers would also bring it all together. I like the uplighting here in the photo you could place along the back fence to add drama. Your area reminds me of Modern mediterranean landscaping.

Yes.. I think you should paint, but... Why not lime wash the walls so you keep the look of timber and get the light, on trend Scandinavian aesthetic. I would go for a very light grey tint with a bright white ceiling and trim. Your fireplace and the deer would be great with this look: a rug and some white and grey cushions of differing textures would bring it all together. Coffee table candles would complete the Scandinavian look. Great room by the way!

Might I suggest a more contemporary picture frame mantel with mosaic stone tile between that and your firebox? Love the near craftsman window shapes flanking the fire wall . . . use the height on both sides, / shallow shelves on one side can visually frame a swing arm for your television and give real storage on the other side.