As a buyer, I paid two lawyers. "the" popular firm in Sosua to draw up the contract and do the closing, and an attorney I trusted from an international firm in the capital to review everything they were doing step by step, unbeknownst to the Sosua law firm. Small price to pay for comfort in a large transaction.
As for closing, mine was fast. Approximately two weeks. I was purchasing a corporation that holds the condo. Title check, etc was done in that period. Process may be more complicated now with some new laws, property surveys, etc.