My gg-grandfather, John Cullen, was born in 1796 in the parish of Daingean in Offaly. His mother (my ggg-grandmother) was Bridget Gorman, who would presumably have been of an age to be an aunt of Margaret, although I don't have any other info about her. If your ancestorrs were from that area, we could compare DNA results to see whether there's a connection. My results are posted at GEDMATCH (kit number T780556).
I also happen to have a Dillon gg-grandmother, but probably not from that area (probably from Tipperary, though I'm still searching).