Well, I don't slur "ye and"; I use a slight clip characteristic of Irish and Scottish-influenced dialects--like the French "h" in "haut". This clip and the reduction also help to stress the "and", as Burke must've intended (it falls on the highest, most accented syllable in the line).

Since this matter has been blown out of proprortion, let me add other considerations: When you sing "you" unaccented in songs, particularly those in "working class" language, do you always use a long U, or do you tend to reduce it? If so, why should you treat "ye" differently?

Singing "yih" or "yuh" in place of written unaccented "you" or "ye" is prevalent in Irish and Irish-influenced dialects generally. What evidence is there of unstressed "yee" in Newfie Irish-influenced dialect--in 1920?

Anyway, the real test is whether it sounds naturally dialect or contrived when you sing it. Even though I'm a pretty good mimic, I play down dialect, since it always sounds falser to folks when they know it's not your native accent.