Mission triumphs only come from the weekly story mission variants - you cannot get them from the normal/legendary campaign Elementary, My Dear is a bit messy since they fixed cheesing it. You need to be in the main areas (Quagmire, Florescent Canal, and Miasma) but the puzzles in there are also hit and miss whether they'll work - maybe its been fixed in the past 6 months and all count in those areas but the last time I tried a few only 1-2 counted. None have counted in the 2+ years since the cheese fix using the side areas.