Why not add a 4th wheel directly adjacent to the (existing) rear wheel. This would allow Aptera to qualify for federal rebates, and would solve the various odd state laws regarding Aptera technically being a motorcycle. The 4th wheel could be smaller than the other three (possibly so that it doesn't even touch the road), and placed directly next to the rear wheel. If it must touch the road, it could trail behind on a loose linkage, with a small shock absorber, such that very little weight is transferred to the road through it (e.g. 20 pounds).
I just don't see a reason why Aptera wouldn't want to be a part of a $7500 tax credit for electric vehicle purchasers. IIRC the original Aptera wasn't going to have airbags, which was ok because it was a motorcycle, but now the new Aptera seems to have all the safety features, so why not add a "tax credit" 4th wheel... it could even be removable by the end user, as federal law only requires the vehicle to have four wheels at the time it's sold.