Will the man with the best boxing IQ in the sport be surprised by his opponent? Absolutely not, no - don't be ridiculous.
I firmly believe both will initially be surprised with the others attributes when they first step in the ring. There really aren't any fighters they can spar to truly prepare for each other. The question is, who will adjust first
Hard to compare the Castillo fight version of Floyd to the one which will fight Pac. I don't think he was shocked by Maidana either - Maidana's style against Mayweather's doesn't make for a pretty fight, but it was just another example of people wanting Maidana to have won the fight, when he obviously didn't.
no floyd has fought plenty of fighters with fast hands and elite agility as of late (canelo, maidana, etc).