John Peter Spiker / John Perry Spiker
Have some further (more accurate?) information regarding John Perry Speicher (Ulrich -> Jacob -> Adam -> Joseph). Shortly before my grandfather died, he wrote some brief notes about the family. Within these notes, he details several family trees including John Peter Spiker (which he details as John Perry Spiker).
Most noteably, his details confirm most of the childrens' names (Jonas, Emma, Harvey, Henry, Will, Mahlon, Norman) with the exception of my great-grandfather John Mahlon (given the birthdate, this would appear to correct the Macolm J. reference). Interestingly, that particular branch of the family (John Mahlon and descendants) went on to use the Speicher spelling of the surname.