I think I would go Canelo, I think it would make for the more interesting fight and Canelo has decent head movement and a decent punch variety, if he could press forward and try to force Golovkin onto the back foot then it could make for an interesting fight.

In all fairness though I think GGG beats both of them pretty easily and there would always be the chance that Canelo would freeze again if he realises that he can't do anything to get near GGG.