Point taken; but there seems to be no evidence that the Water is Wide versions are older than the 19th century. As yet, we don't know for sure that Lani was asking about the whole song family or specifically the well-known The Water is Wide, which appears to have been unknown in American tradition before the 20th century and almost certainly derives, through print, from the Somerset collation published by Sharp.

If she's talking about the whole song family, of course, then all bets are off and you might well be right, though I think that none of the 18th century forms contain the Water is Wide verse.

The Ripest of Apples referred to above presumably did travel to the US from Ireland; the tune used may well have originated there, but the text probably didn't.