I like the idea of doing the herringbone pattern but I would keep the color simple as your granite is beautiful:) What I do love is when you can use the same color in different finishes to add texture. Matte and shiny in a random placement would be beautiful. this is a dark color but gives you the idea. only in certain lighting will it be visible

Yes there are panels but most are pretty tacky looking why not try just some Ikea wall panels .

Cabinets are traditional. The counter is Cocoa Corian. The little bit of wall that is above the cabinets is still undecided as it is an open kitchen, we are not sure whether we should have the same colour ceiling/walls in the kitchen/living space. I am leaning towards keeping the ceiling the same across both spaces but having two different wall colours in the kitchen and living spaces. After a few hours of looking at colours it was hard to choose one colour that would go well with off white cabinets and our beige sofa/chairs. I do not have nearly enough experience to make all of these decisions. I can look at photos of a room and tell you if I like it but I cannot look at paint swatches and small tile samples then visualize it well enough to know if I like it. Ugggh!!

Great ideas. Have you thought about a glass tile in a neutral color- white or cream? This will to add some subtle “bling“ and brightness to your kitchen- complimenting your counters & island, while adding a nice contrast to your wood tones. I always think of a backsplash as a pretty piece of jewelry for the kitchen. Best of luck- Let us see what you choose!