Quest worked for me today (Death Knight Campaign). On completion that seems to be it, but.... Return to Maiev Shadowsong on the Broken Shore for the quest 'Champions of Legionfall' to return to the class hall to recruit another follower.
To do this you must first be on the upper level, take the quest 'Making Preparations' from Darion Mograine out on the balcony.
The comment by 'Boxofbeer' Patch 7.2 dated 2017/4/15 on the wowhead quest page has links to the full chain to recruit the follower Minerva Ravensorrow.
Have to say although the DK is an alt & not my favourite class to play, this was a thoroughly enjoyable series to play through to acquire my class hall mount & pets.