I would be very wary of these kind of coincidences,
Surprisingly, there is actually a lot of this sort of thing going on, especially around the time of passing of a locally notable person, especially a minister or pastor. Or if a youngish person dies tragically. For a couple of years, a lot of kids will get his first and last name as their first and middle name.
Unless there is actual evidence, such as having the exact same birthday or the same relatives, it is probably best to maintain separate profiles for these people for the time being, and then merge them with an explanation about the names if it becomes clear that they are the same individuals.
Since we are talking about a fairly recent time frame, some DNA connection would also help.
So, since you asked, i would say that those 'coincidences' are possible hints at the most, and require a great deal more research.
Keeping an open mind, let's try to find out all we can on each of the names. It is possible that there is a step-dad involved and John Daniel used his step-dad's name at different points in his life. There are several scenarios under which this could all be true, or not true at all. More research required.
Here is an ancestor of mine whose name change puzzled me for a few months:
You will notice that there was more than a few 'coincidences' together that finally convinced me that they were the same person.