[Scotty doesn't know]

I'm almost positive if the coach leaves, it's completely up to the player to make a decision, the school has no say in it.

Nope! Once the letter is signed you are signed with the school not the coach. The school can go ahead and say for everyone to opt out of their letter if they want but it does come down to the SCHOOLS choice whether or not to let them leave. If the player (Lucas) asks to leave Flordia they can force him to honor his letter for that school.