Confusing Tombstone Placed for Mary Fern (d. 1885)

Standing in the Pine Ridge section (block 2, lot 14) of Rose Hill Cemetery is a cross-topped tombstone placed for Mary Fern, who died 27 February 1885. Here's an image (transcription of inscription on and below):

In Memory of
MARY BALEY
A Native of
ARGYLE, SCOTLAND
DIED FEB. 27, 1885
AGED 59 YEARS

FERN
[on base]

I should also note another side of the tombstone bears the name Michael Fern (with nothing further). Cemetery records show he was the purchaser of the family burial lot, and was interred there July 1856.

So. Her name was Mary Baley Fern (where "Baley" could be a middle name, maiden name, or previous husband's surname). Right? This funeral notice from page 5 of the 28 February 1885 edition of the Macon Telegraph (Georgia) seems to bolster the notion:

The friends and acquaintances of Dugal, John, and Miss Mary Fern are respectfully invited to attend the funeral of their mother this (Saturday) morning at 10 o'clock from the Catholic Church.

While trying to flesh out the lives of Mary's children, however, I came across something unexpected. On daughter Mary Fern's 1922 death certificate – with noted informant being her brother Dugal – her mother's maiden name was stated to be Mary Thompson (born Scotland).

After conducting more research, I think I found the marriage record that clears things up a bit. Mrs. Mary Fern married James Bailey 10 March 1860 – about 4 years after the death of Michael Fern – at Bibb County, Georgia.

My Latest Working Theory

Mary Thompson/Thomson married Michael Fern before or about 1840, possibly in Scotland, where at least two (and likely a third) of their children were born. The family was in the United States about 1850, where census records suggest at least two of their children – Dugal and Mary – became naturalized citizens about 1860.

Michael Fern died July 1856, was buried in Rose Hill Cemetery, and the widow Mary married James Bailey four years later. It's possible James died before 1880 (burial place unknown to me). Mary died February 1885, and was buried near her first husband. A death notice appeared in the same newspaper and issue referenced above (28 February 1885 Macon Telegraph):

The death of Mrs. Mary Bailey occurred yesterday morning at her home, 319 Fourth street. She had been indisposed for several days with pneumonia. Her funeral will take place to-day from the family residence.

The three known children born to Michael and Mary – Mary (d. 1922), Dugal (1842-1928), and John (d. 1901) – appear to all have died without issue. Each was buried in the lot at Rose Hill Cemetery purchased by their father, and if memory serves, not one has a tombstone.