Hi. I apologize but the room is so cluttered with painting supplies, ladders in the corner mixed in with baby toys from having just moved in that a pic would be frightening ! I knew this post was a long shot without more detail but thought I'd try. Thank you

happyday123 impossible to say for sure..I wouldn't dare answer this for myself just by looking on screen..you need to see it IRL..with your materials. and seeing whole space is helpful too of course. It matters what space will be taken by your backsplash..are there any windows, lots of space under the hood or not, etcetera of the top off my head though-if your countertop stays..and with your beautiul flooring..gloss if simple shape..matte if textured a bit...ask me why-and I don't know:) I can't base it on anything I can explain, at least not at the moment. Need to think In general agree with eam that any color derived from your countertop can be very pretty..the exact name? no you'll need to look at it. you can like several btw..can happen:) (this fourth tile you've posted..I don't remember others but it's very expensive..to me was a tile I could just kiss good bye:) eam is right asking about budget...it will be taxes, shipping, whatnot on top of the written price. You'll need to order more for possible breakage, cuts, etc. If you have exposed edges-consider that. Trim pieces? Glazed edges? Just sharing my experience..since I never knew I should take it into account until the installation day. Then installation day moves a month since with handmade tile you need to wait..and can be more than a month. Can be 6 weeks, 8 weeks, depending on a tile and how busy they are. Their mistake-they'll expedite it , will be a few days, But if you didn't think of something in advance-it's not their mistake. So take all into account. Maybe you're more experinced than me, and you did..but I was very inexperienced. So. Back to prices. You can get contractor's discount though. They usually build it in the price..theyll ask the name of a pro you're working with. It was 30% off with all the decent stores around us. Which were very few, lol)

Here are better pictures that shows the exact color of the tile & walls due to being taken in the daytime with natural lighting besides the very dim light that was coming from the chandelier

I have a fireplace that is placed almost exactly like yours next to the stairs, and it is framed all the way to the ceiling. Let me tell you, it is a huge piece of architectural interference in the space. I would love to have what you have now, a less-intrusive look. You're also going to lose light from that back window if you build out a huge column there, and I think you'll regret the loss of natural lighting in the daytime for your space. I'm having a hard time understanding what you are meaning about taking tile or stone to the door. I would stay away from anything gray in the space given your floor and wall colors. I would also be very careful about anything "white" that you put on the fireplace as far as it coordinating with your Swiss Coffee walls. You might look into Romabio products for stone. They have limewash meant for fireplaces that comes in several colors.