She was Anna's coadjutor!
If you Google, you get:
The term coadjutor (or coadiutor, literally "co-assister" in Latin) is a title qualifier indicating that the holder shares the office with another person, with powers equal to the other in all but formal order of precedence.
These include: Coadjutor bishop, or Coadjutor archbishop, Coadjutor vicar, or Coadjutor apostolic vicar
Which makes it even weirder that Joey was throwing around Latinisms usually used in relation to ecclesiastical roles when she was hiring Rosli -- isn't the story that one of the children overheard her using the word and kept using it? Poor Rosli. I hope one day she stood in the middle of the Freudesheim nursery and snapped 'The next person to call me by that bloody word is going to bed without their supper! For a year!' 
Also, I wonder what 'faithful' Anna, who dumped her suitor to continue to serve the Maynards, made of someone brand new being hired in on an equal footing...?