I agree with you the pillars are unfortunate. The replacement tiles will stand out no matter how close they come to matching so you're better off making sure they are clearly different so the gray one is better. Putting busy mosaic tiles could look nice but will interrupt the flow between rooms which I'm guessing is your problem with the columns in the first place. You will need to create a dextrous solution to tying into the 2x4 wall on the left side but I think it can be done tastefully- maybe beveling it back once you get past he end of that wall.

I think the roof might be a bit too dark for the brick colour. The bricks and the window joinery will blend in fine. What did you decide to do?

Love blue tiles. Depending on how much sun and how hot your pool gets in the summer should dictate what color it is. We live in Arizona, so cool blues work best. Our neighbor has brown tile and a dark pebble tech pool. Looks like a swimming hole and gets really hot - 94% water in the summer. They obviously didn't think it through.

Beauty and practicality; Mmmmmm ..... When it is something that you love .... real wooden floors. Now vinyl just gets dirty , Ply looses it functionality, real wood however gains a patina. You want that. People pay thousands of dollars for that. Go with the most genuine example that you can afford of what you love. Factor in your budget and add to it, an area at a time and be pleased that your life gives character to it every day. By analogy; A mahogany french polished table will just give you a nervous break down every time someone doesn't use a coaster ... a hardwood table can be replenished over and over with hard wearing protective surface .... which you can repair. If you love it, if it adds genuine warmth and character, you won't mind maintenance. You won't be saying ...." look at this floor , isn't it amazing? It looks just like the real thing?"