Games : Where can I get mage after main quest line is completed?

I had Solas in my party for the whole game time, however he is gone after the main quest line is completed and It looks there is no change to enter quest for get Vivienne or Dorian Pavus (in fact it looks it is not possible even before What Pride Had Wrought quest). I would like to finish some of the side quests and it can be done only without mage in the group or from some old save (and i don't like these options :-) ).

Any advice? Thanks