Others may disagree, but I think 8spd is a good choice for drivetrain durability and indexing reliability.

Cranks are cranks, IMO. Unless you're particularly concerned about weight, there's not a lot of difference beyond aesthetics and gearing options.

It seems you've correctly identified a compact double as a good fit for your needs, but as for the specifics of gearing, you're the best judge of your ideal range by extrapolating from your experience. I'm not sure how much we can help with that.

If you want to work out the shortest high gear you'd be happy with, which seems like a good start, simply figure out a roughly equivalent combination on your current ride and see what you think. As for the low end, that'll involve guesswork. But seeing how you go with more weight should be easy enough... got a backpack?