Does anyone know why Sera is the only companion you can ask to leave the Inquisition? I'm not sure if it has anything to do with your friendship level (as far as I know other companions have disapproved of my actions more than she has) but I'm near game completion and she is the only one who has the 'You don't fit the Inquisition' option available when I speak with her.
Sera and the Inquisition
dragon-age-inquisition
Best Answer
From my researches, there is no "official" answer to your question.
However, there are some character that can be told to leave :
I don't know for sure about the other characters, but it say's here that if their approval drops low enough you can tell them to leave. (Unconfirmed)
I don't think you can get rid of Cassandra or Solas at any point.