Eh from Blenheim On. Canada!!!!!!!

I am a new member here directed by Genealogy Forum Uk.
I am interested in finding all about Francis David McKay b. 1755 Scotland. I believe Francis was born Bridge of Gaur, near, Loch Rannoch. I got this area off a map of Scotland that I brought up on - line, while searching for him. It is believed Francis was married twice, once in Scotland & the second time here In On. Canada. It is his first marriage that I am enquiring about.
Francis David was born 1755 Scotland - d. 1813 Welland, On., Canada his 1st wife maiden name was Foss/Fuss/Friss, her father's first name was Philip. Their children were - 1. Catherine, 2. Elizabeth, 3. Francis ( M ), 4. Margaret, 5. Mary, 6. Peter + a possible 7th. Daniel b. 1798 Scotland ( ? ) - d. 1859 Welland, On., Canada. This is where Daniel lived & raised his family. Daniel is the direct line - of - lineage.
While searching Familly Search I got this information but, I do not know if there is a connection or not. Finlay McKay ( father ), Juncan ( mother ), Kilmadock, Perth, Scotland, child McKay b. 09 Feb 1755. I do not know if this is even rellevent or a long shot, but the birth year is that of Francis, & all this amounts to is a hunch!!!!!!!!!
Any help with parents & dates, 1st wife & parents & dates, all children listed above & their dates for Francis - WOULD BE DEEPLY THANKED OVER & OVER!!!!
Yours Truly
Scratch And Patch