I expect the other states will eventually join NY in the suit.
I hope the taxpayers of those states are happy to see their money flushed down the drain to pay legal expenses for silly court cases.
This suit by the Port Authority of NY and NJ will likely be thrown out of Federal court. I don't see what legal grounds they have to challenge the proposed merger, considering that: 1) the authority to review these mergers is vested in the Federal government, and 2) everything in the Federal process appears to have been done according to the letter of the law.