On Ancestry, there is a public tree which might be of interest to you.
The owner appears to know of an extra son of John Robert Bonoitt.
He lists the 4 children from the marriage with Wynona, as mentioned in the newspaper obituary.
Then another son is listed with an unknown mother. None of the 5 children are named, as they will be living still.
Making contact with the owner of the tree may move you closer to the name that you are looking for.