The fight would be lose-lose for Zab. If he beats Vargas it's no big deal because Fernando is shot and would be too drained from cutting down to 154 (sad but true). If somehow Vargas was able to waddle his way around the ring enough to catch up to Judah and stop him it would be a disaster for Zab.
Floyd knows that controversy and animosity generate interest and increase ticket and ppv sales so he plays the bad guy and collects his check. That's my take.
In addition to the ones you listed I subscribe to Bad Left Hook (pretty good boxing blog), the boxing feeds for CBS Sports, ESPN, LA Times, Yahoo, and The Sweet Science.
I can't imagine even imagine Floyd fighting Cotto, who would be a bigger draw than Cintron or Williams. It'd be nice to see a unified title but I'd settle just to see Mayweather/Cotto.
Celebrity Rules #101: When you're in trouble with the law you have someone from your entourage take the hit. Highly doubt Canelo is snitching on his brother. If I was a betting man I'd put my money on his brother telling him he'll take the fall for this and of course Canelo will make sure he's taken care of financially.