Major question, why is trying to reason with people siding versus Kenny? Seriously, I was just think they could all shut the %*($ up for a minute, let Duck get clean, then see if he had a bite or not. It's not like you turn into walkers instantly.
Shawn still took a while after getting bitten. For the second episode, I assume you mean the high school Coach/Student? We really have no idea exactly when their time of death was, and that was after they were already completely 100% dead, not just bitten.