Platinum Instant Sourdough Yeast - 10 packets

What is the expiration date on these?

Why is the best used by date in a couple of days from when I received it?

Can I use red star instant sourdough yeast in my bread machine?

Are instructions included? I am used to 7 grams of yeast for kneaded bread, and only a half-teaspoon for my no-knead, which I prefer.