It is very true that certain families did appear to have 'affinities'. I have encountered this a number of times.
Crow has not cropped up very often in my Gawne research. So far I only have two other instances.
William Crow who married Esther Christian in Lezayre 1779 (she was a niece of Edward Gawne of Ballagawne's wife, Jane Taubman). Then there was an Anne Crowe, abt 1796, who married Daniel Gawne in Lezayre 1838. This Daniel, from Jurby, was the son of Thomas Gawne and Joney Kneen and belongs to the same family as I mentioned in my other response (Gawne & Tear). In fact this family had a number of Kneen links but mainly in Jurby.
I have a Lezayre marriage for a Margaret Kneen to a John Gawne, 25 Feb 1786, but I have not been able to identify this John yet (their children were all christened in Ramsey).

Jane