I am intrigued by this project.
But first, I need to know if you have your characters already in a .demo format or at least the .costume file you want them to appear in. If so, then a huge amount of work is avoided since they don't have to be recreated in the Costume Creator (Icon).
One hundred characters is an awful lot and I am concerned that either they won't easily fit in the scene or you will have to pull the camera so far back, that they become difficult to see. But, those details can be worked out.
I can't commit to doing this just yet, as it will be a significant time investment. How soon do you want this done?
Here's some of the stuff I've done, for reference:
Some group shots of my own characters,
The Zodiac Guardsmen
The Legio Praetoria
As well as one with my SG mates, 'The Dauntless Reverie"
Like I said, this could be fun and I've been looking for a new Demo project. I ask for nothing in return besides your patience, your cooperation and frequent and effusive praise