There are two different lengths available. 3" & 8" with several boards in the package. Prices may vary by your location. I suggest looking on your local store website is visit the store in person to view the materials in person.
You wouldn’t. These are for a wainscoating for the bottom 3 feet of your wall. You use special molding that you buy with it to hold it in place. Not for a ceiling.
Each piece within the package is 3' high and 7 1/4" wide creating a panel approx.43 1/2" wide. They also carry it in 8' lengths. I used both on my project. Excellent product.
You can paint it any color you wish but I recommend a primer coat before painting.
I would refer to the Manufacturers site for possible outdoor use.
I used an 80 tooth chop saw blade for a smooth cut.
I used it in the bathroom. It's like a vinyl/plastic material. It has held up to humidity but I would worry as a backsplash above a stove, high heat might warp it. If it were me, I would choose a material that is more of a sure thing.
No. It comes in white, but it is paintable.
I used a 90 degree trim molding, 1" X 1".