Whilst I can't find the others, there is a birth for a John J. Bailey in June quarter 1918 in West Derby (which is regn. area where Mary Margaret born/lived) with mothers maiden name as Gallogly on one site and Gollagly on another. I looked at original page and looks like Gallagly. I can't see a marriage between a Bailey and Gallogly/variants and wonder if this is a transcription error and that Gallagly should read Gallagher??
Annette