Yeah pretty much. But growing taters in raised beds makes it way easier to harvest than in the ground.

People who grow them in buckets or crates just tip the bucket out.

As long as the soil is able to drain through it and not sit there for weeks, should be fine.

I don't suspect so - I've never tried it, but I would really like to.

I'm also not sure how tall it can get - depends on your growing season and the plant's lifecycle

You can safely go about 3-4 boxes high for potatoes without risking rot, as long as you've got good drainage and don't overwater - the soil at the bottom shouldn't stay sopping wet.