i have always done my garrison resources missions with my lvl100 follower with the scavenger trait (http://www.wowhead.com/garrisonability=79)
it doesnt matter if the traits doesnt match the mission. u will get on those missions a probability between 50% and 59%, but i have lost my last 8 missions in a row, did i get the unluckiest streak ever or did they change something ?