Are you speaking of the verses such as John 3:16 and Romans 10:13 and any other verse that has the word whosoever? If I am understanding right are you asking that when the bible says whosoever shall..., is it possible that there are exceptions to the rule? For instance using Romans 10:13 where "whosoever shall call upon the name of the Lord shall be saved", are you asking if one could have called on the name of the Lord but not be saved?
So when the Bible says whosoever does not practice ( that’s what diets means KJV) righteousness is not born of God, it means that everyone who does not practice righteousness is not born of God. It can also be stated “If a person does not practice righteousness, they are not born of God
Two things.
1. This is not sinless perfection. It is speaking of what marks our overall lifestyle, love to God and neighbor or sin and rebellion
2. It is a descriptive, not a prescriptive statement. That is, it is not saying we practice righteousness in order to be born of God, but rather it is a result of being born of God, or a DESCRIPTION of one who is born of God
Peace