Finding an excellent lawyer in the US can be tricky. Background reading: American Bar Association, "How Do I Find a Lawyer" and Forbes, "How to find a good lawyer when you really need one."
Beyond word-of-mouth, a starting point can be researching prospective lawyers to make sure they're state bar members without state bar disciplinary action against them, AILA members, have a good reputation for past work, any publications they've written, etc. If the lawyer is part of a practice, also research the other lawyers in the same practice. See AllLaw.com, "How to Find an Excellent Immigration Lawyer."
With this initial research, you'll need to have initial consultations with at least a couple of the lawyers you're considering. They may charge for this. The initial consultation lets you see how the lawyer talks to you about your case and the potential road ahead. Don't trust a lawyer who makes unrealistic promises---but beware that you can't always identify unrealistic promises---this is also why you should consult more than one. Since your case is a bit unusual, the initial consultation can also tell you whether the lawyer has experience with similar cases. Good luck!