Thank you all for your comments!
Russ, I agree with you on the tone...although I am not a heavy user of sepia-like tones, it somehow worked here for me. The organizers wanted something "different", and B&W didn't really work with these kids.
Dale, in the second photo, the guy's long dark hair does seem to loose that separation between the foreground-background tones. I only used one strobe to light the subject, what I should've done was used another strobe to light the people directly behind the subject, this would've also let me stop down the lens a bit.