Hi Win
There was quite an active textile industry in Easter Ross, but this seems to have been in decline after the Napoleonic Wars (so was on the downward slide before the dates your relatives were in the area). I've had a look in a couple of reference books that I've got, but haven't been able to come up with a definitive answer, I'm afraid!
In David Alston's book "Ross and Cromarty - a historical guide" it mentions a place called Gordonsmills (Ordnance Survey grid ref NH 706655) on the shores of Udale Bay (in the parish of Resolis), about one mile west of Jemimaville. It was set up by David Urquhart of Braelangwell. Alston says that there was a spinning mill on this site "under a manager and others brought in who had a knowledge of sorting, scribbling, carding and spinning". The mill was in operation from 1797 until 1815, so unfortunately it stopped operation before your relatives were in the area. Alston also says that there is no mention of wool spinning/carding by the time of the Statistical Account of the parish in 1836.
In Ian R Mowat's book "Easter Ross 1750-1850" he mentions that " a number of attempts were made to introduce a woollen industry ..." one of which was "a mill for carding wool, and jennies for spinning by David Urquhart of Braelangwell ... by 1850 these lesser activities had also long since ceased".
However, there's also mention of a "waulk mill" in this area which is I believe a mill for beating and cleaning cloth but I can't seem to find dates for when this was operational. Perhaps there still was some textile activity in this immediate area, but on a much smaller scale than before - but that's just speculation on my part!
The next nearest major textile operation would have been a few miles away in the Cromarty Manufactory which made rope and coarse cloth from imported hemp. Much of the work was done by "outworkers" in neighbouring parishes so perhaps your relatives may have been involved in this? It operated from the 1770s until 1850. In 1831, 200 people were employed here, but this dropped to 90 by 1844.
Hope some of this is of help!
Lynn