Now, it seems to me the real intent of the thread is to address the attitude that some (many?) have towards other professing Christians who have not yet come more fully into the "truth". The question is raised about the repentant but unbaptised person, "should they be told they are still going to split hell wide open unless they get baptised in Jesus' name?"
I honestly cannot see the situation actually happening, as described. There are two types of repentant persons: the person who hears apostolic preaching, is convicted, and decides to side with Jesus and follow the Lord. Such persons will almost immediately be baptised, almost always that very day. Even if - as is the practice of some churches, sadly - they are told "to schedule a time next week to be baptised" they are not treated by the other believers as outsiders. At least not that I have ever seen or heard of.
On the other hand, the other type of repentant person, is the one who hears preaching by a non apostolic preacher, in a non apostolic context. Such a person will likely be told "ask Jesus into your heart and you will be born again". Such persons may be told to get baptised for the remission of sins (in a Cambellite, Lutheran, possibly Methodist, Christadelphian, Eastern Orthodox or Roman Catholic context) but almost certainly using the trinitarian formula of Rome and not the Bible formula of the name of Jesus Christ. So what of these?
Are these people repentant? Is the Gnostic repentant? The Mormon, the Jehovah's Witness? What about the Muslim convert, for that matter? They have amended their lives, they have "stopped the sinning" they were so used to, they have "turned over a new leaf". Does heaven rejoice over such persons and their change of life? Sure. God and heaven always rejoice whenever and wherever righteousness and goodness prevail over evil and wickedness. Are such persons Biblically "repentant"? That is, have they REPENTED in the Gospel sense?
I think in most cases, NO. Repentance implies more than just that the thief stop stealing or the adulterer stop adulterating or that the liar stop lying. It implies a turning FROM SIN (as such) and a turning in faith towards God through Jesus Christ. It implies hearing the Gospel and saying "yes".
Have such persons heard the Gospel? Not have they heard something about someone called "Jesus" but have they heard the Message ordained by God and delivered to the apostles and sent forth into the world? I don't doubt that many people have heard about Jesus, been drawn to him, and for whatever reason take a long time to come to the waters of genuine apostolic baptism, travelling through many winding and twisting roads of erroneous theology to wind up in the end at the Truth. His sheep hear His voice, through all the din and bluster of the world's religious nonsense. Eventually they come to Him.
ANYONE who professes belief in Jesus should be welcomed, and encouraged to continue with God into all the truth. Anyone who balks at the truth, at whatever step along the way, either doesn't understand what is being presented or is proving they are "not all of us". Not everyone claiming to belong to Jesus does in fact belong to Him. Time tells all, and we are sanctified by God's Truth, that is what sets us apart. So those who REJECT truth simply identify themselves with the world and its errors.
But anyone who shows up to an apostolic meeting, having previously been to the local Baptist evangelist's rally, and got convicted and decided to give their life to Jesus, will be GLAD to hear about
Acts 2:38, they will be GLAD to hear about the Holy Ghost, they will be GLAD to be exposed to the Truth in all its facets, because if they DID repent, then they have a love for the truth and will follow the Spirit's leading into all truth.
Otherwise, they never had it to begin with.
So no, we don't need to tell someone "hey you repented but you haven't been baptised yet, see? So you're on your way to a devil's hell for real for real no cap." no, we should simply tell them "Ah, great, you have decided to follow Jesus! Well here is what He said, and what His apostles said, about how we are to follow him, so come along with us together to the City of the King!" If they refuse? Then they judge themselves unworthy of eternal life.