re, #1. If anything is wrong with the trust documents, then you may be subject to loss of the NFA items and/or criminal charges. Some people would rather pay money upfront to ensure that doesn't happen. Many people would rather take the chance. There has been at least one guy who had a major legal problem stemming from the way his trust was set up. My take is that it is probably a good idea to pay the lawyer to do it right if you will have anything other than a one-person trust.
#2. See #1 and lawyer.
#3. Get a referral from guntrustlawyer.com