Edmund James Anderson is actually a grandson of Robert and Mary, rather than son as suggested on the tombstone, the son of their oldest daughter Ann born before her marriage to James Waddell but probably his son (guessed by the middle name of James). His birth and death registration give no father's name.
Elizabeth was actually aged 3, her birth was registered middish 1865 and her death was registered as age 3 in early 1869. After her father Robert died tragically in 1874 her mother Mary had the headstone engraved for him and for Elizabeth. She was illiterate. Edmund's name was added in the space later, then much later her own name and deathdate.