Torque
#2
I am no means a mechanic, but with the drain plug on my 13 eco i always just get drain plug tight then snug it up without over tightening it,dont think many people actually change the gasket either unless it looks worn or oils leaking around plug. Some may think otherwise tho
#3
I beleive the tq spec is 19 ft lbs. as far as changing the gasket for that bolt, I don't think it's necessary unless it is leaking. But you can its pretty cheap to do but probably a bit of over kill. Good luck.