Particularly I am thinking of 係員, 係官, 担当者, 主任, 主任者, 責任者, and 担任.
I know that 担任 is almost exclusively used for teachers/education but there are examples outside of this (weblio examples: ある仕事を担任する, 1874年兵庫新川開鑿事業担任に任命). Is this more of a deprecated use, or is there some pattern for when this is used in other contexts? Also unlike the other forms I used, it usually doesn't refer to the person in charge, but simply the action, but again, there are exceptions.
係官 seems to be used for government officials that in charge of something.
But the nuances between the rest elude me. Is my understanding of the above correct, and what are the nuances with the others?