It would really be up to the Supreme Court. They would have to rule on the constitutionality of a state revoking their ratification and the question of the Congress imposed deadline.
It is worth the try however.
No. I am not sure who would be in charge of determining the answer to these questions when figuring out if a constitutional amendment was successfully ratified but it absolutely must NOT be the Supreme Court. For the Supreme Court, the legal body that is supposed to be determining what violates the constitution to also be blatantly deciding what is in the constitution in the 1st place would be a very disgusting mockery of the principle of separation of powers that defines the workings of the country.