I'd limit the number of codes to just a few, but also have a sentence or two to describe the situation the code implies.
- Im--Imperial member world, with various Imperial facilities and organizations, military bases, and associated nobility. Subject to Imperial Laws.
Cs--Imperial Client State world, independent from, but allied to, the Imperium. Could contain Imperial facilities and organizations and military bases, and may have its own military bases.
Na--Non-aligned world, which may be friendly, neutral, or hostile to the Imperium, and having other relationships with different interstellar governments. May contain a small Imperial presence, if friendly, like a Scout Base, but otherwise, all facilities are owned by the planetary government. May host a base of another friendly interstellar government.
As for Aslan, Va for Vargr, etc., etc.
Additionally, Cs and Na worlds should have the die rolls and DMs to determine if they have major local government bases present in this section, I would think.