LaLiberte Family Genealogy Forum
Well, Mary and Marie are just english and french forms of the same name. Many people of this time period didn't know how to write and so it is likely that a priest wrote many of the records you are talking about. Mary->Marie is an easy transposition, phonetically with a french accent. =]
Further, christians of Canada in this era named almost all females Marie-something, and went by the middle name.
A great many families took on the name of Laliberte when they came to the new world, though I have not run across any Laney->Laliberte's before, it would not surprise me.