Maria won't abuse her precious maid; on the contrary, if anyone even looks at Fantine the wrong way they will be thrown out the window. Maria's HQ will most likely be a mansion with the perimeter consisting of high walls and guards at every corner-tower.

Edit: Depending on if you're going to RP Fantine as a separate character, I might actually make some changes to Maria's characterization and make her a bit more sympathetic, with more of an emphasis on her trust issues and fear of being inferior rather than the sadistic and cruel focus she currently has, since I didn't think she'd have a meaningful relationship where she could develop in the RP. In Tvtropes terms, Fantine could serve the role of a Morality Pet to Maria.

To Maria, something that still has use for her is not expendable, which means as long as she thinks Eponine and Fantine are loyal to her she won't think of them as being expendable. That is, unless her paranoia starts acting up, depending on the circumstances.