What does the word ‘reconcile’ mean in the context of ‘all things,' when Colossians 1:20 says the fullness of God was pleased to reconcile all things to himself in Christ? For starters, the context indicates they are really and truly things – that is, the impersonal portion of the general Creation of which mankind is only a part. Moreover, 'reconcile' has a certain semantic range which is not so narrow as eternal reward for all, irrespective their faith in Christ in this life.
But 1 Corinthians 15:19 talks about believing in vain, and if we hold fast, with regards to being saved. And that makes less sense if all will be saved in the end, albeit most after a period in Hell, as the Christian Universalist would say.
Meanwhile, all being made alive and resurrected in Christ is actually about all being raised from the dead, either to eternal life in the New Creation, or else eternal conscious torment in Hell. That is, on the Day of Judgment, all must be resurrected to stand trial.
But all things being subjected to the Son should be thought of as martial, of a piece with conquest. And the passage says “all things;” and that is distinct from “all persons.” Yes, all men are related to all things, since the Creation was not subjected to futility willingly, but eagerly awaits the revelation of the Sons of God – that is, we who are in Christ, who are the elect.
I think there is a category confusion for the Christian Universalist, supposing that subjection of Creation generally implies restoration to glory for all men as created beings. Always in the Bible, unless I have missed an example, 'Creation' refers to the impersonal, and is as distinct from mankind as the Heavens and the Earth; though mankind exists on the Earth, or instance, and is made from the dust of the ground, he ceases to be the ground from which God made him when the breath of life is breathed into him by the Almighty.
But where Paul says he is telling us a mystery, we do well to take note that the meaning may not be apparent or obvious at first glance. That is what it means for something to be mysterious. And if God gives us the victory through Christ, the passage does not say that God gives all mankind the victory in Christ, irrespective belief or unbelief in Christ.
Notice in Romans 5 the frequent use of ‘we’ and ‘our’ throughout the first two paragraphs. That is exclusive language, and Paul is writing to Christians in Rome rather than to all Romans without exception. Yet here we also see Paul talking about ‘all’ with regards to sin and death in Adam. And when Paul talks about the grace of Christ, he says it abounded for many. Yet he does not say it either did abound for all, or will abound for all. Rather, he says ‘for many.’
But then Paul says the one act of righteousness leads to justification and life for all men. And the use of the words ‘many’ and ‘all’ is set up or those who were first made sinners and then righteous, in the first Adam and the second Adam respectively. But those many and all who have been justified are the ‘all’ contextually who had previously stood condemned in their sins, and otherwise would be condemned. They are not all men irrespective of faith in Christ.
The hermeneutics of these passages must be seen as a street that is meant to be driven in one direction on when you are in a certain lane. That is, one could drive northbound in the southbound lane; yet we readily recognize, in context and by paying attention to the signs, that we are not meant to drive northbound in the southbound lane, and will have accidents if we try to anyway.
In short, forever and ever must mean the same thing for the smoke of torment for those who worshiped the Beast and took its mark as it means for God living. So also, to deny the eternality of the punishment for the ungodly similarly undermines our confidence in the eternality of the promise of life for those in Christ.