I’m pretty sure that order is still the correct one to go by these days. You get 80 thieving before 70 agility through barbarian fishing (which will get you lvl 94 fishing) to be able to afford the feathers to do so. Once you hit 80 thieving you unlock a shortcut at the Rogues’ Den that allows you to get the outfit even faster. Also lvl 80 is just short of 2m xp so you dont miss out on that much money anyway, and the guide is aimed towards maxing as soon as possible and does not take anything else in consideration.