OK, I should answer your original question regarding the marker stone. Yes, it was very common to erect a stone to mark the family plot. There were many, many disputes over who owned what ground, so parishioners (all over the country) were advised to "mark their spots".
I have a monumental inscription for the Hodge plot but no picture of the stone, I will check tomorrow, it should be still there but perhaps it's in bits, it was an obelisk. The transcription was done in 1982, on my old Remington typewriter, so (after advice from the Scottish Genealogy Society) the text was put into order of - husband - wife - children - etc and all relationships are to the first name on the stone but the inscription on the actual stone may be in a different order.
"Obelisk. William Hodge died 10th February 1910 aged 84 years. His wife Mary Ann Reid died 13th February 1899 aged 72 years. Their son William died 3rd January 1866 aged 2 years. Their daughter Mary died 10th December 1871 aged 24 years. Their daughter Maggie died 10th July 1876 aged 23 years. Their daughter Elizabeth died 21st September 1883 aged 32 years. Their daughter Jeanie died 25th February 1895."
From the gravediggers Day Book, the above Mary aged 24 years was a teacher, interred 13th December 1871. The above Maggie (Margaret in the Day Book) aged 23 years, was a school mistress, her abode was given as Falkirk, interred 18th July 1876. William was aged 2 years & 6 months, interred 5th January 1866.
From the Plot Book for the old churchyard (This book only begins from around 1876).
all dates are of interment.
Owners of the above plot were William Hodge & Mary Ann Reid.
Interred in the centre compartment -
MARY HODGE, aged 72 years, 16th February 1899.
WILLIAM HODGE, aged 85 years, 12th February 1910.
Interred in the north compartment -
ELIZABETH HODGE, aged 32 years, 24th September 1883.
JEANIE HODGE, aged 37 years, 28th February 1895.
From the records of the municipal cemetery (adjacent to the churchyard).
Plot C476.
MARY ANN R. KERR, Wishaw, aged 19 months.
Parents - William Kerr & Robina R. Hodge.
Interred 17th February 1886.
ROBINA R. KERR, housewife, Wishaw, aged 29 years, married.
Parents - William Hodge & Mary Ann Reid.
Interred 2nd December 1886.
ARCHIBALD KERR, Wishaw, aged 15 months.
Parents - William Kerr & Robina R. Hodge.
Interred 10th March 1888.