In my readings after coming across and raising a few box turtles, i have found that it is possible to sex box turtles based on the color of their eyes
Thats all well and good, you can sex budgies on the colour of their "nose"(too lazy to find out right name), but thats budgies and turtles, not some biped that was spotted by a 6 year old 14 years ago by a lake.
Could the op tell us if there is any high schools nearby or water parks/fun fairs? Im sensing a scooby doo storyline.
As for the snakes, have you checked under other rocks? Have you checked the same rock at different days? It may be a perfect location for them to hibernate for the winter hence the congregation of them there on a yearly basis, or it could just be a snake pub.
Think its unfair for people to jump to the conclusion that its a female 2 legged dog person who may or may not be gender confused.