"Now we see dimly as in a mirror, then we shall see face to face." -1 Corinthians 13:12.
I don't think we'll have complete knowledge of any of these things until glory, but I do think that it is important for us to be informed in these issues so that we have greater knowledge and understanding of God. All collections of "secondary doctrine" as you call it, which I would define as: "doctrines that do not determine whether or not a faith is considered orthodox", follow some kind of historical tradition of interpretation. For instance a more pentecostal reading of the text follows the tradition of viewing the role of the H.S. in a very prominent and externally obvious position, and this changes how one would view all different "secondary doctrines." Open theists have a very relational view of God, so do Arminians, while those following the reformed tradition have a God that is "higher" and less susceptible to change. Your entire theology can be changed by how you approach a certain doctrine, which means that most views of "secondary doctrines" develop into systems with similarities but not necessarily the same views on different subjects.
For myself, I see myself strongly in the Reformed Tradition, but I leave room for a more Biblical reading of the text as opposed to the strong Systematic reading of my tradition. My strong belief in the sovereignty of God affects my soteriology, my approach to the text affects my eschatology, and these all inform each other. I think that this is the best way to approach theology, but I am not about to die for any of these doctrines.
I hope this helps,
“The Bible is essentially an open, artistic, imaginative narrative of God’s staggering care for the world, a narrative that will feed and nurture into obedience that builds community precisely by respect for the liberty of the Christian man or woman.”