For mashed potatoes we use a 'passe-vitte' (French) or in Dutch 'draaizeef'. Don't know the English name, if there is one. Even better than doing it by hand (well, the thing works by hand and it takes a lot of time, but boy, it's way better).
I'm Belgian. We are part of the French kitchen.

#16 or cut the onions under your kitchen fan

#17 depends on what you are going to do with the meat. I don't like to let a steak rest because I want it on my plate, hot and leaking into my mashed potatoes. No juice is lost, it's just redistributed.