No we don't fly in formation and no,there is no currency requirement for crashing,either on land or water.Practising it makes the plane difficult to use again.
The longest overwater part of this flight would be POP to Grand Turk,less than 30 minutes from land.The rest of the journey follows the Bahamas chain and I have done it quite a few times without feeling the need to crash.
It's a nice flight.