So it's a Guild for lone Assassins? There seems to be no actual leadership, besides the interaction between Equipment and Intelligence Departments with the rest of the guild.
I'd reserve a rank for "Squad Leadership", and keep only one of the this-assassin-is-more-roxxor-than-the-others-rank. Also, I'd rename the Intelligence and Equipment Department to make it sound as nice as the other ranks. I'd make it look like they are still assassins, but they also do something else.
Here's what I mean:
1 - Wannabe
A member who hasn't participated in any kill.
2 - Rookie
A member who has either participated in three kills, or killed someone himself.
3 - Assassin
An experienced murderer, gets his orders from the Ringleader.
4 - Ringleader
Distributes jobs for the assassins and leads them in high rank jobs.
5 - Slayer
An Assassin charged with the Highest Rank jobs.
6 - Investigator
Charged with identifying and studying bounties and competition.
7 - Fence
Manages the Guild's storage and disposes of looted goods.
8 - Protagonist
Distributes missions to the Slayers and Ringleaders. Also acts like a representative of the Guild.
9 - Master Assassin
Head of the Guild, decides which missions to keep and, along with the Protagonist, the rank they belong to.
Structure:
The Assassins' Guild is a guild focused on assassinations. They receive payment from outside sources, who wish for the death of someone. Most of its members are secret, though some Protagonists are visible for the public to contact with the guild.
I'd do something like that if I were you. Less talk in front of the ranks, more talk about the structure and purpose and workings. Hope you like the ideas.