I'm so sorry you are having to wait so long. On our first bid, we waited quite some time for the sellers to sign. When it came back from ROFR, it was not passed as the sellers misrepresented the points. We went back and forth with an agreeable solution, resubmitted and Disney said it wouldn't work because it involved transferred points (they transferred to make up for missing points). So, we cancelled the transaction and received our full deposit. It did waste 2 months though. When we should have been getting our points, we had to start over. Our second contract (with a different company) took 2 and a half months to close, and information was not very frequent either.
I would call and email any and everyone involved - broker, closing agent, etc. Tell them you have serious concerns and ask when they anticipate closing will be. Let them know that you will be willing to walk away if the contract is not complete by the contractual date (if that's what you want). But know, that you will be starting at ground zero again. If they can get the sellers moving, and be more forthcoming with information, it might be easier to just wait. You are really close and starting over would take a much longer time.
Often, holdups occur due to the seller taking time. In both our cases (2 different companies), we had to wait for sellers. Even if you move on to another contract, there is no guarantee that you will have a quick, smooth transaction.
Good luck! I hope it moves along faster from this point!
I'm also wondering if they are international sellers. Not sure how you screw up signing the documents. You just find a notary and sign on the line in front of them. Not rocket science.
Maybe they forgot the notary part?