Mark, it appears that one of the biggest problems you're running into trying to document the father of John Oliver Neville (Neville-2363) is not using sources to decide who's who.
As mentioned above, your original post regards the comparison of two unsourced profiles.
Reminder: the Honor Code that all members agree to emphasizes the value of sources! Without source documentation, we can't objectively resolve conflicting information. The comparison of the two unsourced Jacob Nevil/Neville profiles is a case in point. Referencing unsourced family trees found elsewhere won't resolve the conflicts.Those other unsourced family trees are ONLY the opinions and possibly just guesses about relationships.
The use of sources to document relationships, dates and places, can't be emphasized enough, Mark.
At present, quite a few profiles related to the Neville and Williams families are unsourced and/or poorly documented, and merges and changes have been made without careful consideration. As a result, Jacob Nevil is his own grandson, etc. Those profiles have really become tangled, Mark.
Before complicating the relationships further, I would strongly suggest you go back a few generations and make sure each profile is well-documented with sources, and relationships are clearly and well established.