Hi. I had a few spare moments and thought I would look to see what else you were researching. Doesn't look like you got a reply. Might these be the people you are looking for? If so, it seems they were born in Co. Monaghan, Ireland.

IGI shows that Catherine Fox married Francis McKenna 27 June 1873 in Hutchesontown, Glasgow, Lanarkshire, Scotland. IGI shows the birth of a Thomas McKenna, b. 14 Sept. 1874 in Hutchesontown, to Francis McKenna and Catherine Fox. However, I didn't find any other births when I did a parent search, but then most of the births may have been after 1880 so not in IGI.

1901 Scotland Census
Name: Francis McKenna
Age: 47
Estimated Birth Year: abt 1854
Relationship: Head
Spouse's name : Catherine
Gender: Male
Where born: Glasgow, Lanarkshire
Registration district: Hutchesontown
Civil parish: Glasgow Govan
County: Lanarkshire
Address: 177 Uries Row
Occupation: Coal Miner
Household Members:
Name Age
Francis McKenna 47
Catherine McKenna 46
Charles McKenna 18
Catherine McKenna 15
Francesico McKenna 13
Elizabeth McKenna 9
Esther McKenna 7
Nellie McKenna 3
James Dalziel 31 son in law b. 1870 Glasgow
Agnes Dalziel 23
James Dalziel 1
Source Citation: Parish: Glasgow Govan; ED: 33; Page: 2; Line: 22; Roll CSSCT1901_309; Year: 1901.

1891 Scotland Census
Name: Francis McKenna
Age: 42
Estimated Birth Year: abt 1849
Relationship: Head
Spouse's name : Catharan
Gender: Male
Where born: Ireland
Registration Number: 282/5
Registration district: Lochee
Civil parish: Liff, Benvie and Lnvergowrie
Town: Dundee
County: Angus
Address: Keirs Back Land
Occupation: Quarry Lab
Household Members:
Name Age
Francis McKenna 42
Catharan McKenna 40
Maryam McKenna 16
Francis McKenna 15
Peter McKenna 13
Barbra McKenna 8
Briget McKenna 5
Elisbeth McKenna 1
Elisbeth Thomson 18
Source Citation: Parish: Liff, Benvie and Lnvergowrie; ED: 1; Page: 51; Line: 17; Roll CSSCT1891_97; Year: 1891.

1881 Scotland Census
Name: Francis McKenna
Age: 35
Estimated Birth Year: abt 1846
Relationship: Head
Spouse's name : Catherine
Gender: Male
Where born: Ireland, CO Monaghan
Registration district: Blythswood
Civil parish: Glasgow St Mary
County: Lanarkshire
Address: 42 King St
Occupation: General Labourer
Household Members:
Name Age
Francis McKenna 35
Catherine McKenna 27
Francis McKenna 4
Patrick McKenna 2
Bernard McKenna 45 brother b. 1836 Co Monaghan Ireland
Patrick Trainer 24
James Cooper 21
Thos Ronaghan 22
James Trainer 16
Michael McMurrough 21
Bernard Keer 4
Francis Hanlon 21
Source Citation: Parish: Glasgow St Mary; ED: 4; Page: 6; Line: 10; Roll cssct1881_230; Year: 1881.

1851 Scotland Census
Name: Francis McKenna
Age: 5
Estimated Birth Year: abt 1846
Relationship: Son
Father's Name: Patrick
Mother's Name: Helen
Gender: Male
Where born: Ireland
Civil parish: Houston and Killellan
Town: Houston
County: Renfrewshire
Address: Houston Village
Occupation: Scholar
Household Members:
Name Age
Patrick McKenna 46
Helen McKenna 40
John McKenna 20
Catherine McKenna 15
James McKenna 14
Patrick McKenna 11
Margaret McKenna 8
Francis McKenna 5
Source Citation: Parish: Houston and Killellan; ED: 2; Page: 8; Line: 46; Roll 774; Year: 1851.

The 1881 census indicated Catherine was born in Co. Monaghan, Ireland, in 1854. However, her age varies quite widely among the different census records, so that date may not be very reliable.