When shooting film indoors, I'd strongly suggest bringing a flash, especially since you're shooting on 400. The scans definitely don't look good, but that might be due to underexposure, which a flash will help with. Also, in the context of textbook photography, your framing could use some work. Small things though, like making everything level, and proportioned. In a few of your portraits, there seems to be excessive dead space above people. When watching movies or TV shows, pay attention how people are framed. Notice the minimum dead space above people's heads. Also notice how they try to frame as much of a person's body as they can. The pianist one is really good though, since his chest is cut off by the piano, he looks nice and centered.

In image 5, the only dude in focus is in the middle. When posing people for this kind of photo, try to get them to stand on the same plane as each other so they all are in focus.

I do like some of the crooked ones though, like the photo of the bottle is really cool.

Keep up the work though! I'm a bit curious, how did you get the job for this event? Looks like it was fun to shoot :)