Only someone who is not using their God-given reasoning ability blindly believes everything in the Bible to be literally true.
There is a growing consensus that large sections of the Old Testament are not meant to be literal histories but are more allegorical, while others recount actual events. Some books are "literature" (Job, Psalms, Proverbs, Song of Solomon, Ecclesiastes, etc), others are "historical" (I/II Samuel, I/II Kings, Ruth, Esther, etc), others are "prophetic" (Revelation and lots of the major/minor prophets) ...
I think the most sensible interpretation of the early bits of Genesis are that it is allegorical, for example. If you look at the cosmology presented there, it looks very much like the cosmology understood by ancient peoples. In other words, it was presented in a format that the people of the time would understand and was supposed to communicate important truths, but is not meant to be taken as a literal scientific account.
But to answer your questions specifically as I'm not trying to dodge:
1a. No. I believe there was not a single worldwide flood. I do believe there was a massive regional flood though, as does virtually every ancient historian.
1b. Yes, in a general sense. Literally everyone believes we are descended from an initially limited gene pool.
2. Yes, I believe the Hebrews (although perhaps with less of their own unique identity at the time) were enslaved by the Egyptians and that there were a series of miraculous events and divine intervention which led to their freedom. And yes, I do believe they eventually conquered Canaan, as the existence of the Kingdom of Israel reflects.
So, we're back again to my original point, where I don't believe in the Dragon - not because it's not as I wish it to be - but because it doesn't exist in the universe that I know. If someone says there's a dragon, I doubt them merely because there are no hexapod reptiles in the fossil history.
We both know the Bible isn't literally true. I knew that you knew that. But, the God of the Bible doesn't exist because so much of it is allegory, and then it's up to each individual Christian to figure out which parts are allegory and which parts aren't. A god that actually commanded the murder of gay people in Leviticus is a completely different entity that didn't do such a thing, but was misrepresented, for example. We then describe 'God' to each other, with no real insight to figure out which acts were actually done by God and which are allegory and which are purely man's invention. We use the Bible as insight into what other people believed about God, but using as insight into God Himself is much, much more difficult.
You talk about "God-given reasoning", but there's just not enough information in the Bible to really discern the true nature of God.
For example, the freed Hebrews didn't actually genocide the Canaanites. How would a 5th century Christian know that by 'pure reasoning'? This poor chap is left with a dilemma. Does he love a god that occasionally commands genocide of people? Does he reject such an entity as not actually being 'good'? Does he use 'reasoning' to deduce that such an entity doesn't actually exist? I can reject that described dragon, because I have the advantage of knowing more. But they're stuck on whether to believe something based solely on its moral description.
Jesus suggests that we 'love God', but how can we call it love when we'd believe such wicked things about Him (without evidence?). The 5th century person can either believe the book or believe their heart. OR, they can create a theology where somehow God is good despite ordering such genocides. It's like, I dunno, justifying my dad's murder of my mom's previous boyfriend when he's actually completely innocent of such things. "Even if he didn't, it would be okay if he did". Barf.
Which is one of my criticisms of Christianity itself - it doesn't proactively look for evidence that their God isn't evil (like their Bible claims). It instinctively
first tries to create justifications for those evils of which God is innocent. This isn't a personal relationship with God. The one thing we truly know about God's nature from the Bible is that He doesn't mind the libel enough to do anything about it. Jesus told us to love God, and so I consider that to be Christian. If someone chooses to believe lies (or even just bad things without evidence) about God because they'd prefer to believe the Bible, I call them a Biblilian. I love my dad enough to look for every piece of evidence he's not a murderer. I don't go to seminary to write essays on how the murders he commits are justified.