Middle initials are very unreliable in my experience - if the other details fit (such as his and his parents' places of birth, and names of other family members), I would not reject just based on the middle initial.
For cemetery information, have you tried searching on Find A Grave for the county or counties you think are most likely? If you know where close relatives are buried, I would look there first, as families tended to use the same cemeteries, especially if the deaths were relatively close in time. And if you are very, very lucky, you may find photos of gravestones with inscriptions like "wife of," or "son of," or similar information.
Good luck with the search.