He created the product foreknowing (possibly even foreordaining) the flaws therein. He saw it coming, and proceeded anyway. I don't say this to blame Him, as I don't think God is to blame for anything. But it does raise questions about the usual narrative put forth surrounding the concept of sin and the role it plays on this plane of existence. It leaves God looking rather inept, I'm sorry to say. And as one who is convinced He is anything
but inept, I find it surprising that churches would perpetuate such a narrative.
If our salvation isn't to our credit, our doom can't logically be to our discredit. It doesn't follow. What you're proposing is what's been termed "doublespeak".
So how can dead people be held accountable for anything? They're dead. They're entire unable to do anything.
Reason isn't a bad thing.

In fact, one would be well-advised to be highly suspicious of any teaching that asks you to put your brain in park in order to receive it. I'm not saying the left side of the brain should call the shots 24/7; I find that spirituality benefits greatly by letting the right side take over for awhile (especially since we're not going to have an answer for e-v-e-r-y-t-h-i-n-g before we die), so that our relationship with God doesn't grow dull and dry. But, ideally, reason should have, at the very least, helped in the construction of the foundation of one's beliefs. Faith's already got the whole belief that there is a God at all in the first place covered quite well.
No worries. It echoes a lot of what I myself accepted for many years.
Sorry, I think you have missed out some key points there.
If we understand Holy Scripture as truly God's Word - as spoken through His prophets, apostles and His Son - we know that Scripture should only be interpreted by Scripture; not by our own situation and presuppositions. Here reason plays a part in accordance with the Holy Spirit. If we can't understand a passage, we first look at the immediate context, and then we can look at everything the Bible has to say about the matter. We can read Scripture in its plain and literal form, unless there is anything in the passage to indicate that it should be understood symbolically. Through this process reason is due.
However, Scripture also presents us with many paradoxes; here we need to tread carefully and be mindful of our sinful inclinations, through humility and fear. When talking about unsolvable Biblical paradoxes, reason easily becomes destructive and counter-intuitive to anything good and spiritual, for it is dealing with things beyond our comprehension. This is not the same as "parking the brain", as you put it.
If you look at history, you can find that many heresies are born out of a good and zealous intention of explaining or defending a particular doctrine, which may look attractive and make a lot of sense. However, due to their over-zeal in defending something, the teaching becomes pushed to the extreme, and in the process throws out and abandons other truths, and ironically ends up destroying the faith it set out to defend. One of many examples of this is the problem I pointed out earlier: Christ's two natures; this cannot be reasoned with, yet it is true, and so it is apprehended by faith.
In a word: More often than not, to reason with a Biblical paradox is to set ourselves up for heterodoxy or heresy.
What you're getting at in your post is the philosophical problem of evil, which could be summed up this way: If God is good, why does evil exist? The answer would typically boil down to that either God created evil or that God is not in control, or simply that there is no God. However, these are false conclusions and contrary to the Word of God. What we can know is that God is omnipotent, omniscient and omnibenovelent, and that He is also entirely good and holy. The existence of evil is unsolvable through means of human reasoning, but it's not impossible through faith, for God is higher than any seemingly impossible logic. God is greater than math!
In other words, if we somehow construct a scenario whereby God is not the source of evil, but due to His foreknowledge of sin, we think that it yet amounts to the same as God being the source of evil, we are in grave error, for this is not what Scripture speaks. Only God is good, and sin and rebellion is our own fault.
I'm surprised by your notion that salvation should be credited to us. How so? The Bible explicitly says otherwise. We are saved by grace through faith; a gift from God, lest anyone should boast. Again, there is only one name by which we are saved: Jesus Christ. Again still, Abraham's faith was credited to him righteousness. Are you suggesting that we can merit our own salvation? In which case, I would suggest reading Romans (and really the entire New Testament) again. If you believe that we add anything to our salvation, then this becomes Pelagianism or Semi-Pelagianism, which is highly problematic in itself.
Also, if I understand correctly, you seem to think we are not ultimately to be blamed for our sins; that sins are merely a side effect of our current condition, and not our own doing. This most certainly goes hard against what the Bible has to say about sin and rebellion, in view of our call to repentance. Jesus even specifically called us "evil". When I referenced Scripture saying man being dead in sin, this means spiritually dead. If we read the full context of this, we can understand that this means that we are slaves to sin, which is a direct consequence of our own doing, and therefore our own fault. Scripture does indeed teach that we are to be held accountable for our sin, and only by God's grace, are we made alive and set free in Christ.
I have a lot to say about this subject but this post is already quite long and I want to stick to the question I posed twice now:
Where in Scripture does it say that whoever, through sin, rebellion and unbelief rejects God's grace, namely Jesus Christ, will have life? Nowhere. In fact, Scripture explicitly screams the opposite! However, if you believe you can find some Scripture to back up this view that whoever rejects Christ will have life, even a hint to it, I'd be interested in hearing it.
May I also add this: If you hold that all will have salvation, do you believe that even the fallen angels will be saved? In which case, how do you get around 2 Peter 2?
Lastly: Do you deny that it is good and righteous for God to punish evil and sin?