The marriage record should be available through Ramsey County, Minnesota who have the records.Be aware that the civil records kept by the counties were not very informative -- often not naming the parents.If they were married in a church, you would get more information from that record.
As to whether his father as born in Ireland or Canada, I always take the information given at the time by the person himself as being more likely than given by an informant on a death certificate who may not have known for sure. Ditto for the name of his father. As late the 1930 census, he indicates that both of his parents were born in Ireland.
The 1905 Minnesota State Census indicates that he had been living in Minnesota for 15 years; ie, since 1890.