George William Kingston and his Elizabeths

I'm just starting to look at George William Kingston and try to find his parents. George was born in Ireland, so that is a hurdle to start with. But, according to my family's history, he was married to an Elizabeth Lantry, born in 1818 in New Hampshire. We don't have her parents, so I thought I'd start with her. I found two census records and one family record. The first census, in 1857 in Preston, Fillmore, Minnesota, records George married to an Elizabeth who was two years older than him (which would put her birthdate around 1807) and who was born in Minnesota. The second census, dated 1885, records an Elizabeth Kingston living alone (since George died in 1865) who was born in 1818 from New Hampshire. And the family record has George married to an Elizabeth Thompson. Two different Elizabeths?