At this point, the science can end and the fiction can take over the train of thought. The fiction author can ‘spin’ these questions to include the influence of the knowledge transfer that might take place using the ancient crystal skulls (as in the Crystal Skull Trilogy).
From the end of Crystal Gift, we know that Susan Mathews as pregnant while still using the crystal mask and crystal skull to extract ancient information. From the story in Crystal Grotto, we know that Alpha was able to reach out and control the thoughts and actions of Princess (the dog protecting Janet). What if, while Janet was still in the womb, Alpha was able to pass along some information or knowledge of the ancient society (passingly referred to as Atlantis)? What if the cave in the Superstition Mountains wasn’t the only massive crystal knowledge repository (there is no reason that there weren’t multiple crystal hearts scatter around the globe).
From the mind of a fiction writer comes a continuation to a story that almost ended. If you remember from the end of Crystal Grave, there was a small opening for more stories. My first thought was to let Jake Roads live on with more adventures. As my mind wandered and pondered, a new story line blossomed. Stay tuned for more as this new story takes on a life of its own.