Sorry If I bug you too much with my questions. I'm really looking forward to this RP, and I wanted to check on any details Maria needs to know for her to be a convincingly competent politician and future usurper.

Like Stern suggested previously, ACA could be divided into ranks for ease of understanding. Here's my suggestion on how it could go, in addition to other suggestions I have regarding ACA's structure.

-At the top is "Our glorious leader", or the Queen as I like to call her, who rules over the entire Aurora City and the domains inside it.

-The Queen has divided the city into six domains, 
one directly hers and the other five assigned to her vassals, whom I like to call Nobles.
The Nobles are responsible for managing the production of Grief Seeds, part of which is shipped to the Queen as tax, the state and growth of the magical girls in their domains and also public relations with the populace. Maria would be a Noble in this system.

-Under the Nobles are magical girls I suggest are called Knights, who serve as enforcers of the Nobles' will and carry out tasks assigned to them by the Nobles, such as Witch-hunts, territorial disputes and other matters requiring use of force. Knights have their own territories as a part of a Noble's domain where they operate, and may optionally govern directly in surface matters.
Nobles would have 2-3 Knights on average in their domains. Eponine and her slums would be an example of a Knight and her territory.

-Optionally, there could be a rank under the Knights codenamed Squires, who would be rookie magical girls yet to properly act autonomously (magical girls tend to be naive and immature due to their recruiting age), and thus are led by Knights as they learn from them and eventually become Knights themselves through experience. While magical girls of any rank could die to a Witch given the circumstances, their body count will most likely be highest among the Squires, which would make Knights and the magical girls above them veterans in Witch-hunting.

Anyway, this is just a suggestion, so don't feel bad about rejecting it if you don't like the idea.