My McGinnity line came from the Tullygillen area of Drumsnatt Parish in County Monaghan. Owen and Alice (McCarville) sailed from Liverpool to New Orleans. No evidence of a PEI stop. The McCarville's, on the other hand, had a number of them stop, and stay, on PEI. The McCarville's were from County Monaghan as well.
I don't have much info on the Gallagher's.
Hope that is of some help.