Sorry, MIs not a lot of help. I've interspersed what I've found in your text.
DJD

There are several possible mothers' burials in Patrick, but only two I found for possible fathers:
SHIMMIN, Catharine Patrick 16 Apr 1804 WIFE of PHILLIP
Patrick MI
Old Yard
# 241
Here lieth the body of CATHARINE ....immin alias QUINE wife of ....IP of Kirk Patrick who departed this life ..nd 180.. aged ...
Here lies the body of ......... SHIMMIN (rest of stone eroded)
Burial register has Philip bur 28 Jun 1822
Philip s/o Philip/Cath bur 15 Feb 1792
SHIMMIN, Catharine Patrick 1 Dec 1806 burial register has Cath widow bur 31 Nov 1806 NO MI
SHIMMIN, Catharine Patrick 7 Apr 1809 burial register has dau of Thos

SHIMMIN, Philip Patrick 28 Jun 1822 MI above eroded
Will: SHIMMIN, Philip 1822 Pat E 2 [LDS film no.] 0106423

SHIMIN, Margaret Patrick 31 May 1817 NO MI
Will: SHIMMIN, Margret 1817 Pat E 2 [LDS film no.] 0106419
SHIMMIN, Margaret Patrick 9 Feb 1823 burial reg has "of Greebey" NO MI
SHIMMIN, Margaret 79 Patrick 15 Mar 1842 burial reg "pauper" NO MI

SHIMMIN, Thomas 81 Patrick 19 Jan 1842

This Thomas above was aged 80 in the 1841 Patrick census recorded in the previous household to Thomas Shimmin aged 45, Ellen Shimmin aged 15 and Elizabeth Shimmin aged 5. No sign of Margaret. Both Thomas Shimmins Ag Labs.

Margaret Shimmin d.1842 above, was aged 77 in the 1841 Patrick census, independ., with Elizabeth Bell aged 2.
So unlikely to be the husband and wife Thomas and Margaret [Craine].
If the one Thomas burial was correct, then Margaret must have been one of the earlier burials. With luck the 1817 one, who has a will.