When I was back in this cemetery this past year, they were nowhere to be found. Those stones were standing solid when I first saw them, I don't think erosion from weather in just over 15 years would have damaged them that much. A lot of rain and strong winds might have toppled the tall ones, but not the one that was only about a foot high. I think it might have been vandalism, but I'm not sure.
Haven't we all found tombstones with a wrong date or name? In the movie "The Shootist", John Wayne's character J B Books ordered his own tombstone, unheard of in 1901. It was simple - just his name and birth date. I'm sure those dates were correct since they came "straight from the horses mouth". I know of a couple of my relatives tombstones that have incorrect dates or no death date. That's the nice thing about preordering tombstones today. It should help future family history researchers, especially when much more information is there than just a name and dates.
When a rural cemetery isn't mowed, I won't walk around in tall grass. I have yet to run into a snake, but I know that day will come. It's nearly impossible to walk around a cemetery looking for a name and not occasionally step in a hole. I've stepped in several and been lucky that I haven't sprained an ankle. One day I fell into one up to my knee, grateful I didn't get hurt. Later that same day, I saw a skunk about 10 feet in front of me. I slowly walked in the opposite direction keeping my eye on the skunk and I watched him go down in to a hole. The thought had never occurred to me before what might be IN a hole! All the more reason to watch out!!