IMO the second option order should go to Jamaica, regardless if it's open gangway or not.
The first option order will most likely go to the B, C, D trains due to 8 th Avenue CBTC, which will require the A, B, C, D to be 100% NTTs.
The MTA needs to exercise the second option order because ridership is growing and it will continue to grow as more real estate is being built. Also, the r46's won't last beyond 3 years.