Okay, sorry for the delay in responding properly to your inquiry. Sleep and a big project get in the way. At any rate, emplace is a legitimate word and denotes (connotes?) a more deliberate or perhaps permanent installation. One places the plate on the table. One emplaces a walkway or building or such. I considered emplacing a more appropriate word because headstones are more than just placed on top of the cemetery grass. Does that answer your question? Could I just as easily have used placed, or installed? Yes. I just happen to like unusual words. I don’t presume to be an English expert but I love the flexibility of our language and try to use what I consider the most appropriate word whenever possible.
Good explanation! Thanks, and yes, it does indeed answer my question.