The mystery dragon fruit might reveal her true identity in a couple of months. I discovered a flower button which will develop into a bud and then a flower. If I'm lucky enough to harvest mature fruit, I can find out what color fruit flesh the plant produces. Of course I'll never be 100% positive as to its variety, but I'll settle for knowing the color of the flesh. The color doesn't matter to me so long as the flavor is excellent.
On a side note, I have been watching certain areoles on the mystery plant for 2-3 weeks because they seemed to be swelling slightly. It's amazing how fast the button appears seemingly overnight. I check my plants daily, and there was no button. Then, bang! There is the button.