(1) Equating "Yellow Fever" with malaria: I was relying on my notoriously porous memory and may have used the wrong scientific/medical term for the old colloquial disease-name. My father contracted a disease in the South Pacific during WWII colloquially known even at that late date as "yellow fever"; I thought it was technically known as malaria but may not be remembering accurately. It was definitely a liver ailment which was treatable with penicillin but from which he never fully recovered.

(2) "Lake(s)," singular or plural: Current day usage says there is one and only one Lake Pontchartrain, but there are three adjacent lakes which could easily be considered a single "system" or whatever.

(3) As far as the song's "Irishness" is concerned, I've just taken that as a given. Have I been wrong about that? In any event, the only important event in the history of the Irish in New Orleans (that is, anywhere near Lake Pontchartrain) is the digging of the New Basin Canal and the attendant loss of many many lives ~ so many, in fact, that Irish immigration to the area came to an immediate halt. Irish-American people in New Orleans fall into two categories: (a) descendants of Irish who immigrated to this area 175 years ago and who generally intermarried/interbred with folks of other nationalities, mostly other Catholic/immigrant groups like Germans, Italians, French, etc., and (b) people like me who moved to N.O. from other parts of the US where most Irish immigrants had settled in the years since the 1830s.