Loose end tied up

Over the years I'd often idly wondered whether or not there was a connection between my BAIN ancestors from Caithness, and those of a BAIN family with origins supposedly from Caithness, who lived in my childhood district (Central Otago, NZ).
Failing a connection to mine, what about one to the other BAIN family who also arrived in Dunedin about the same time, give or take 10-20 years, in the 1860s/1870s?
Attempts at connecting the latter BAIN family, that of William and Jacobina (MANSON) BAIN to my BAINs had failed, but we did end up connecting them, distantly, by the MANSONs.

The Central Otago BAINs worked back to a William, butcher, brought up in Kaikourai, Dunedin, emigrating about 1857 from Wick with his parents.
His marriage certificate said his parents were a George & Jessie BAIN and the most likely candidate was George Traill BAIN in Dunedin, BUT George and Jessie hadn't married until 1864, which didn't really "fit".

This week an idle web search brought up an article in the Otago Daily Times (the Dunedin paper) about a BAIN family reunion last year for descendants of George Traill BAIN and included a snippet that George had emigrated with wife Elizabeth, dtrs Catherine and Margaret and son William, in 1862 on the Silisia, wife and an infant dying on the voyage. George's cousin Janet later coming out to look after the children, and then marrying George.
Bingo.
This was sufficient information to identify the likely family as being that of William BAIN & Catherine SUTHERLAND of Thurdistoft (1841) then Tain (Catherine, 1851).
A fellow member of the Caithness Family History Society's message board had provided their 1841 census details some years ago, and it included Margaret, Catherine and William, of the right ages.

After all that it doesn't look as if they're likely to match my BAINs of Latheron (Clashscribie), but it was a satisfying loose end tied up.