I didn't read the entire thread, so please excuse me if I'm being redundant.
1. You're doing a terrific job and please accept my compliments.
2. Deadbeats are deadbeats, don't let them stress you out.
3. I would suggest that those that fail to produce, not be permitted to participate until they have fulfilled their earlier committment. Even if there are individual extenuating circumstances, this would be fair.
4. Please refer to point #1