I never stop any torrent & just leave them seeding
Yes fup limit incl both upload & download as far as I know. I know my usage is exceptional hence said that 3.3TB per month limit won't affect more than 99% of users.
Never, using torrents regularly on mobiles is worst decision for battery as well as mobile life. However I do know someone who download around 100gb daily using Vi night unlimited binge plan on poco f1 & realme U1 each.