Only one census (1880) has Isle of Man which does create some doubt. I have seen a lot of Manx people with England as birthplace on US census records but you usually get a mix of England being entered for some years and Isle of Man for other years. It would be helpful if anyone can find any more mentions of IOM on the US records for this John Teare to support further searches of IOM records.

I can't find a marriage record although some US marriage records provide little information about the people's background anyway. Is there any information on the death certificate about his parents' names and the birthplaces?