The Robinson connection?

Two more, potentially related, lineages have been added to the One Name Study lineages section:

• John (or Robinson) & Rachel (CAIRNCROSS) FAIRBAIRN
• Robert (or Robinson) & Mary (WILSON) FAIRBAIRN

By dates, it is unlikely they are father (John) and son (Robert), but both seem to like Robinson as a first name.
What is the connection between them and where in Scotland did they both come from?
Rachel was in Jedburgh in 1841 and daughter Margaret moved to Newcastle.
Son Robinson moved to Australia.

Robert & Mary lived in Newcastle but Robert was born in Scotland.
Son James appears to have moved to Pembrokeshire.

Any direct male line FAIRBAIRN descendants around willing to take the plunge and join the DNA project to test where the lines may "fit" and whether or not they are related to each other?

26th: Yet more entries for most inventive indexing: Patriarchs update

More entries for the most inventive indexing competition:
I'd not found a Rachel FAIRBAIRN I'd been looking for, she was clearly FAIRBAIRN on FreeCen, but ancestry for some obscure reason had her as FREEBURN, a common enough substitution.
Her son Robinson however took the cake: JAEBAIRNER.
Other recent "entries":
FRANBURN, FAIRVAIRN and FAIRBINEN

Another outline tree has been added to the Patriarchs page, a family with Durham, and a bit of Yorkshire, thrown in for good measure, that of John FAIRBAIRN and Mary CROMBY/CROMLEY/CROMEY (married 1743 Whickham, Durham), depending on how you interpret the family bible (CROMBY or CROMLEY), and the Northumberland & Durham FHS indexes (CROMEY) on FindMyPast.