Hi Metty,
I will see if can I help you.
You have obviously collected their names from something, if you know that they all arrived together, you must have had access to the emigration records. I believe that your answers lie in Canada. Are you able to find any marriage or death records for them? These records might include the names of the others ie if one of them died would the records include the relationship of the informer etc. If you could find out where they were buried the cemetery may have memorials that might indicate who they were as very often memorials state that this stone was erected by....in memory of his brother etc. I gather from others that Canadian records are not great. I have access to Roots Ireland, alas it does not hold records for the years that you require but it holds the following records:
Mary Ann Grier
Date of Baptism: 13-Jun-1824
Address: Parish/District: BAILIEBOROUGH
Gender: Female County Co. Cavan
Denomination: Church Of Ireland
Father: George Grier Mother: Ellen Grier
There was also Elizabeth Grier Date of Baptism:04-Mar-1827 born to this same couple.
This appears to be their marriage record:
24-Aug-1819
Parish / District: KILLINKERE County: Co. Cavan
Name: George Greer Elinor Kellett
Address: Monaghamore Bailieborrow Envigaroge
Denomination: Church Of Ireland Church Of Ireland
Occupation:
Age:
Status:
Husband's Father Wife's Father
Name: Greer Kellett
What this proves that some Greers did not emigrate, there was also a family in Knocknalossett in Knockbride. Those that I looked at were Church of Ireland (Anglican rather than Presbyterian)
Land records are used where no other records are available so I looked up Griffiths Valuation and found the following Greers in the Bailieborough area
Greer James Monaghanoose Bailieborough Co. Cavan
Greer Joseph Carnalynch Killinkere Co. Cavan
Greer Robert Glasdrumman Knockbride Co. Cavan
Greer Robert Knocknalosset Knockbride Co. Cavan
Grier James Drumoosclin Bailieborough, Co. Cavan
James & Robert may be the same persons as these farms of land would be close to one another. This survey would be taken circa 1850, the names do repeat some of the names you have. I wonder did any of them emigrate to the Greers you mention. Chain migration did occur.
Working back to the Tithe Applotments one name was found in 1833 Grier JosephCarnalinch Killinkere Cavan.
I also consulted articles relating to the Church of Ireland in Bailieborough but found nothing relating to Greers. The old Church of Ireland graveyard is transcribed but many stones are illegible. The newer part has not been transcribed. If the Church body has records you should contact https://www.ireland.anglican.org/about/rcb-library to see what they have. Otherwise contact Cavan Genealogy Centre, for a fee they will also do some research for you.
Contact Details
Irish Family History Foundation
Cana House
Farnham Street
Cavan
Co. Cavan
Email: enquiries@rootsireland.ie
Also utilise any resources available at https://genealogy.nationalarchives.ie you may find a will that could refer to family in Canada. I hope I have given you a little more to work on, sorry I was unable to find the answers you require.
Regards Carmel O'Callaghan