The Trader and Colonel Gearheart are the same person.First, they look similar. The part of the Trader's face that we do see looks kind of similar to the bottom of Gearheart's face. The two wear similar-looking clothing. Also, Red is Gearheart's main color (meaning it's presumably the main color of Gearheart Arms Inc). The trader's submarine is also Red. Furthermore, as evidenced by their character entries on This Very Wiki, they are both Only in It for the Money. Lastly, I can't be the only one who wondered where she got the keys to the Mega Crab. It makes sense if you consider that Colonel Gearheart has direct access to Dr. T (and the keys to his superweapons).
WMG / Boom Beach