> cemetery rules as outlined in the contract the plot holder signed upon buying the plot <
I think you hit upon the key point right there. What does the contract say?
The contract specifies rules for planting and decoration, specifies the size and style of monument and what quality stone is permissible (equal or better than Barre Gray) If, say, the stone is 7 and 3/4 inches thick rather than the specified 8”...it is refused. All size specications, which vary from section to section must be mat exactly. If the monument has a discrete picture vs an inscribed one it is refused. It must have Christian symbols centrally prominent and unencumbered by other design elements. If the stone cracks or constitutionally degrades or erodes in any way, ever, the stone dealer must replace it. That’s just off the top of my head.