I may,only may,have found a family connection between John Sutherland,adjutant captain of the Galway Militia and one of the proposed candidates for Lady Ann(e)-Ann(e)Caulfeild nee Bermingham,
2nd Countess Charlemont.Whether it is relevant in the context of the tradition of passing the portrait is another matter.
Ann(e) Bermingham of Rosshill is connected to the Browne family,original owners of Rosshill,by virtue of Eiizabeth Browne,sister of Peter Browne,marrying John Bermingham.I haven't worked out the precise relationship of Ann(e),born 1780,to this John,born circa 1668,via her father William,but the relationship seems to exist
http://landedestates.nuigalway.ie/LandedEstates/jsp/estate-show.jsp?id=724The Peter Browne referred to above had a son John,(1st Earl of Altamont),who married Ann(e) Gore,daughter of Sir Arthur Gore,2nd Baronet.
This Ann(e) Gore's brother Arthur(1st Earl of Arran) had a daughter Lady Joanna Gore,herself a candidate,previously proposed by me,by virtue of her being known as Lady Anne Daly,following her marriage to Michael Daly of Tokay Lodge,Clontarf Dublin.
Katherine Daly,the granddaughter of Michael by his son Denis,married Captain John So(u)therland in 1809.
I'm sure it would be useful to try to fit dates to the characters,and draw a mini family tree,but my head hurts(again)!
Regards
Roger