re: Do they know our plays?

This line of thinking is completely over played in fandom.

Any decent college football player with adequate film preparation can tell you 3 or 4 likely plays based on down, distance and area of the field before they see the offense line up. Once in formation a player can normally chop that down to 2 or 3 plays. Once the ball is snapped if they read their keys correctly for the D that has been called they usually know what play is coming.

This is why coaches talk about execution way more than play calling...it is also why fans who didn't play at that level often talk about play calling more than execution.

It's a nice thought to suggest a coach break their tendencies more, but tendencies are what they are for a reason...1) it fits the philosophy 2) they are a result of their strengths 3) sometimes you have to take what a great DC gives you, etc...