Forgive my interjection, but it seems there is a greater question afoot, which is the function of conscience.
Most of the Scriptures quoted have to do with guilt vis-a-vis God. We sin against Him, but He forgives us with His infinite love.
The problem of Humanity is accepting that love and forgiveness that we know we are not worthy of. So, the question is this: if Eternal Damnation is reserved for the enemies of God, and Kingdom of Heaven is for those who love God (however imperfectly), what of those who have grave misgivings regarding their deeds once they pass? Does God force them into heaven? Does God overcome their will in order to force them to choose entering into rest?
To be honest, until the General Resurrection, all of us are in an 'intermediate state.' The Church rejects the idea of Purgatory because it was taught as being 1) material, 2) temporal and 3) punitive. However, there is sufficient experience of the Church that some people after dead struggle with their consciences. I don't think there is anything revolutionary about that. God allows some more time to pass into rest, and we can offer prayers for them as a consolation and help in that process. Nothing more. God does not force anyone into His Kingdom, and there is no Scriptural evidence as to the exactness of the process of death or the exact nature of the conditions of souls after death. There are parables and snippets, but one can hardly argue that there is immediate post-mortum deposition of the soul from the New Testament. So, both sides argue from silence when it comes to the Scriptures. The 'Particular Judgement' is shrouded in mystery, as well it should be. Repentance is aided with a little uncertainty. Even St. Paul spoke of it (1Cor9:27).
So, a true Sola-Scripturalist has to shrug and say, 'I'm not entirely sure what happens until the Last Judgement.' That's fine because it is honest. One of my Evangelical seminary professors said it in a systematic theology class.
Anyway, I think that prayer, even when it is misguided (imagine all the times we have prayer fervently for someone we thought was in trouble when they turned out to be quite well) is of benefit to those who pray. It is an act of love, which must certainly be helpful. Of course, too much obsession with it in a particular case can lead to all kinds of weirdness as we have seen historically, but I do think that flippantly condemning it may lead to other problems as well.