Sincere apologies for not getting back to you sooner.You provided an amazing amount of information.I expecially appreciate the 1910 census information.
My stumbling block for William being (per your information) the son of a James Hennessy is that I now have his death certificate, which states his father was George Hennessy.It gives his mother as no first name) Coon.
The frustrating thing about this death certificate information is that it led me to the perfect Michigan couple: George Hennessy and Ada Coon, residents of Pawpaw, Michigan.They had several children during a reasonable timeframe to have been William's parents, but no William.In fact, his 1889 birthdate (tombstone and death certificate) would have made this impossible unless he was a twin...which is, of course, possible.
Again, I apoligize for not getting back sooner.Life intrudes at times.
If you have any ideas that might help me resolve my puzzle, I would appreciate them.I hope you are having a wonderful holiday season.