Yeah, that would have been quite a good solution to it. Looking at the amount of empty mugs on the table, I'm not sure if it could have been possible, though. People aren't exactly getting smarter the more they drink.
They aren't in Renji's group because Renji picked all the good ones. These are the bottom of the barrel types. In Renji's group they would be long dead, every single one of them. It would actually be interesting to know what sort of monsters Renji's bunch kills for work, but it must be at least the bigger and meaner goblins that made short work of the MC group, if not something still more dangerous.