How long is this gig? Is there a contract? Is the option to still instruct an option? This offers the flexibility that you can easily cancel students to do a trip for the new boss(make sure the students understand ahead if time the terms as well).

Only 200hrs a year, that's a lot of spare time to be exclusive to one individual, unless they have the above mentioned contract, and you need to be compensated accordingly.

Are you getting a type also? Once again, state this in an employment contract.