Now for the crowd.
Leather-Masked Figure
The person on the far left looks like they're wearing some sort of leather hood/helmet/mask, with a tube in the front -- with the way it's pieced together, it resembles a primitive gas mask. But that's not even the weirdest thing about this one. If you look closely, you'll see a couple of little bright orange circles. That's the fire in the background. You're seeing through this person's head. Also, note the copious head-spikes. Kinda weird.
The next person to the right looks pretty male, and looks nicely dressed, with some kind of weird dramatic collar-like thing at his neck. I think he's wearing a headband, or maybe just a bandage for a head wound?
Spikes
The next person, towards the center, looks female with short hair, but could easily be male. Wearing a yellow coat? With shoulder plates and spikes. Looks kind of mercenary. Has a nice shoulder-slung satchel with a steel(?) buckle. But the elephant in the room is that they have spikes in their hair. Does this mean they're not human? Those little bald patches -- are they spots where the spikes have fallen out or been removed? Do they have anything to do with the other spikes we see in this scene?
And on the far right, two women, one in dark blue with very elegant patterns on the back, and one in plain light blue.
Cone-Hooded Priest(?)
A bit further ahead in the crowd, on the left, we see someone wearing a hood that presumably marks him as of the same order that the floggers on the platform are from, and at least as high-ranking as the one administering the beating; he gets a pointy hood, while the underlings on stage have more subdued hoods. On his back is probably the insignia of the order: a very wide and short rectangle, connected by a short line to an equally wide circle. Of course, it might not be their symbol, but it could also be a symbol of rank.
On the right, about the same distance forward, is a man in a yellow-and-red... poncho(?). At the very least, this tells us that those exist in this world.
Other Spikes
And at the forefront of the crowd, we see two more figures with head-spikes or horns. One's pairs are curved, while another's pair is long and straight. These may be helmets, or they may be directly protruding from their heads, like with the central figure in the back. However, these symmetrical horns they bear look quite different from the asymmetrical little nubby spikes on the figure in the back, so they're probably not the same phenomenon.
The last figure is all in white, and may have the same kind of headband as the second one in the back. The rest don't appear significant.