I have been wondering the same thing. The William that married in 1828 is the head of the clan in Aberdeen. I am very keen to identify his origins so if you know of any spare Williams then please let me know.
I didn't really respond to your own request for information. The William who married Margaret Jamieson is the only son of the above William. They had 11 children in all although not all survived their early years.
My side of the family descend from their son William (born December 1862 - the one born in 1960 died earlier in 1862). He led the emigration to the US, although they had also spent time in Leith, Edinburgh and in North Shields. Family members were added at both locations.
Another son, Hardy Robinson, started off another branch, some of whom also went to the US although a number are still around in Aberdeen. (I discovered yesterday that there was a cotton magnate in Aberdeen in that era called Hardy Robinson. Since he lived in a mansion with a host of servants I think our family, in somewhat humbler circumstances, may have named their son after him as a joke!)
If you want more details of the Aberdeen people, please get in touch. I'm starting to fill in the gaps since I can't get further back than 1828 at the moment.