I called Dr. Allen the other day and what I took away from the phone call was that essentially you can carry on business as usual with privately owned Muscovy that do not inhabit public bodies of water, ie lakes, rivers, & streams. The regulation is going into effect March 31st as is but they are working on re-working it to acknowledge both utility & exhibition birds to the best of their ability while still protecting the wild birds in south TX and allowing states to control feral Muscovy populations. As the regulation already states that you can retain Muscovy you already own, there will be no problem "owning" Muscovy even after the regulation goes into effect. He said that they will not be hunting people down who have Muscovy or who buy Muscovy after the regulation goes into effect.
He also stated that he would like to receive Emails from people regarding two things at this point, A). how you utilize Muscovy in your situation (i.e. pets, meat, eggs, insect control, etc.) and B). How the regulation can be re-worded to account for domestic, privately owned Muscovy. He would like these Emails sooner rather than later so that they can move forward to get this regulation changed.