How many different kinds of interesting things, here; I'm sorry I can never make your walks. (I need a lot more advance time to plan that kind of trip.)

My guess on the stone with no dates and the loads of pictures & stuff is that either (a) they are macabre & like celebrating Halloween or (b) they got the reservation in advance, made the stone as is, and one of them passed away recently and the death date hasn't been inscribed yet. I'm leaning towards (a) though.