The store can cut the section but generally with not rip cut anything with a width of less than 12”
You can, but I wouldn't. For your front porch, I would used treated 2x4 and maybe cut them down and stain them to last. This would is more of a hobby/project would that I didn't have to joint and plane prior. I used this wood to make a decorative box for my wife to fill. (see picture below).
You can, I wouldn't. This is more of a hobby wood.
Not good for loading.
Absolutely nothing st Home Depot.
Would not be good word to use for stair tread you need a much harder And thicker would.
Generally speaking you get two free cuts.