It isn’t extortion, but like the earlier poster said, it is a bit of poker because if you walk away and foreclosure happens, the second lender is screwed. Possible to ask the first lender to pitch in, or start over and submit a new offer that specifically says the first lender must pay the second lender from the purchase price. Your strategy will depend on how much “action” there is on the property, too.
Also, don’t be afraid to ask all realtors to pitch in some of their commission to make the transaction happen.
But, before asking for concessions from the first lender and realtors, make sure everyone believes you can and will walk away.