Hi David, you said, "I have discovered information in census records, marriage records, and death records of his immediate family that confirm his middle initial is 'R' and his birth year is 1870".
Census records: Only one census record of John contains a middle initial. That is the 1870 census, and the initial is an M.
https://familysearch.org/ark:/61903/1:1:MD8Y-S9G
Marriage records: John’s record in Ancestry’s “Alabama, U.S., Marriage Indexes, 1814-1935” does not include a middle initial. FamilySearch has a record in their "Alabama Marriages, 1816-1957" database with the R. initial, but as we cannot see it, we do not know if it is correct and not a transcription error. Both marriage records are transcribed. I have not seen the actual marriage record, have you?
Death records: The death records of his children Mary, John, and Robert do not contain a middle initial for John. Those records are attached to John's profile.
Are there other records that you know of that contain an R.? If so, can you cite them on his profile? Otherwise, the only historical record not transcribed is the census with the M.
If the census records are correct, it seems John was born before 1870 as most of his census records include a birth year prior to 1870.
It seems his parents are Albert and Susan until there is a better candidate. Hopefully more records will become available to help confirm this further.