Way too much case law and specific law in Georgia to support legal self defense with any weapon available. Including felons. Separate charge could be made if the possession was illegal depending on circumstance.
No specific Georgia Code forbidding possession, only federal law.
It costs little more to form a trust, and there would be NO legal problems ever for wifey to hold/possess/use any NFA item in the trust.
As the NFA approval is about a year now, just cancel the application (ATF will refund the 200 bucks) form a trust with HeavyD, and resubmit for the SBR stamp.