Hi Alexander, Welcome. You may care to look at a couple of the Surname DNA Project pages: the Patriarchs page has at least 3 versions of your John & Elizabeth (YULE) FB tree. I was rechecking some of the data on that line just the other day and wondering where Sanna got the born Makerstoun from for John, which shows on the version that I've checked more of the data for. http://www.worldfamilies.net/surnames/fairbairn/pats?raw=1#yulehttp://www.worldfamilies.net/surnames/fairbairn/pats?raw=1#yule will open at that version, and I suggest using your browser's find facilities to get at the other two. None of which answer your "where to from John back?" question, at least not with any certainty.
However, if you are really curious as to which of the other documented FAIRBAIRN lines may bear closer scrutiny, I'll push my usual barrow of "have you considered joining the Fairbairn Surname DNA Project?" Right now would be an excellent time to be in as the company we use has just announced specials for December for kits ordered via a project. Details on the project blog http://FairbairnsAll.blogspot.comhttp://FairbairnsAll.blogspot.com Your line is not yet represented at all. (I am assuming from your name and interest in this family that you are a direct male line descendant from John not from a maternal line of descent).
Just in the last week or so we've had a really good match between three of the lines which have resulted in a revision of the chart that attempts to link assorted trees together - love to know where your line "fits". Check out the theoretical overall lineages: http://dnasurnames.info/lineages/dnafairbairnlineage1signaturecharts.htm#clump2charthttp://dnasurnames.info/lineages/dnafairbairnlineage1signaturecharts.htm#clump2chart
As to John's origins: IF all children are known, and accurately documented, and IF they followed the Scottish naming pattern, I would expect John to be the son of a James and Lucia, but most trees assign him to a John and Lucy (EADSTER) FAIRBAIRN, with many trees then trying to say that this John also married Helen ANDERSON and getting their dates rather confused when compared to actual records.
Archibald and Marion (DICKSON) FB's son John was born in 1760 in Kelso, with their marriage giving Archibald as of Nenthorn and Marion as of Smailholm, which doesn't "feel" like the right sort of area for John and Elizabeth's family, and would make John and Elizabeth's first son James born when John was 17. Not impossible, just not very usual.
I'll send you a private message with more details.