Just got back from vacation and haven't spoken to my cousin yet.I think you probably have more info than I have but I will get back to you. Anything you can provide about the Philip McGuigan family would be helpful.
Rose Ann McGuiggan ultimately married David Lavelle in Newark, NJ in 1887. Although not certain, I have the impression that the families knew each other before emmigrating.
David was from Armagh. A few years ago I asked a friend who was visiting Armagh to look in the local phonebook. She couldn't find any Lavelles but did find a few McGuigans(the connection?).