I ordered by reprint of Col. Bell's book from Picton Press.
Col. Bell identifies Johannes and Henry as probably being brothers; however, it seems more likely that they were first cousins.Also, most references I have seen given dates of 1701-1791 for Johannes which seems at odds with your information.
Other references show them as descendants of a Hans Dubendorffer and Ragul(a) Schreiber.
I'm trying to piece together anything I can on the Diefendorfs during the period prior to the Rev. War.Tuf job.
Do you know whether the info you have gave from microfilm from FHL or a personal visit or what?