If you like it, do it! There's a sconce for every style fireplace. If you can, find an actual-size picture of the sconces you're interested in, and before you buy them, tape them up on the wall for a couple of days -- or weeks -- to see how they look.
, your fireplaces are lovely. The way you've decorated them absolutely complements their style.
And I certainly woudn't call 2cold's
rooms formal as much as I'd call them traditional. There is a difference.