I'm compiling a database on Mathiesons of all spellings in West Central Scotland up to about 1880, and I've done some research involving your family line. This has included the Poor Relief Records for Paisley and Abbey Parishes held by the Reference Library in High Street, Paisley. These show that Farquhar Fraser Mathieson was born 7 Oct 1864 in Paisley, son of James Mathieson and Janet Johnson, married Neilston Parish 11 Aug 1849. James was born in Paisley about 1820/1821, son of Roderick Mathieson and Mary Gordon, and it was this Roderick that had been born in Inverness, not Farquhar or his father James.
I have a lot more info culled from Poor Relief records and census returns etc which may be of interest to you. Please mail me direct for more details.