I don't know how to respond to the list of questions you made. To me, they do the job of inferring or implying an infinite regress of irrelevant inquiries pretty well, but the problem with equating them with the question of whether or not Adam & Eve could have left the garden is that those questions aren't interesting to me & this one is. So if you're interested in whether or not Adam & Eve argued in the garden, I suggest you explore it.
I'm going to try once more to take your supposition that historical-contextual reading of ancient texts is a necessary aspect of gleaning a proper understanding of said text as a given. I don't know how that will fly because it's something you demonstrate implicitly as well as explicitly to be a primary focus. So if all discussions of questions about shared mythologies need to touch on this methodology, fine, but I'd like to consider it touched upon & proceed.
I'll try to also clarify that in my usage, “broader” means broader, not better. So when I suggest there's a broader way to see the question, I'm trying to say that simply because we've run aground with regards to a necessarily narrow scope, it's possible to open the inquiry to other influences. It's an experiment, not an exegesis.
I keep hearing sentiments & statistics on the state of our (broadly) culture regarding religiosity that don't bode well for the organized of faith. Something like 40 percent of folks between the ages of 18 & 40 don't consider themselves part of (affiliated with) any sort of religious tradition. As you go over the age of 70 the number is something like 3 percent. I don't know if I have the numbers right & I'd point out the statistic doesn't seem to hone in on people's personal beliefs per se, only the propensity to belong to communities of faith. But, now, well, there are all sorts of reasons this state of affairs might be playing out, generationally, as it seems to be at the moment & I think the question about Adam & Eve's agency to abdicate is more aptly placed in this context than into a treatment of “reading-for-meaning.”
It's a personal question more than it is a textual one: let's try to write the question in this way—rather than “Could Adam & Eve have chosen to leave the garden?” instead, “Do I have to play by the Christian Bible's rules?” It's perfectly reasonable to read the question this way for a number of reasons. I'll name one.
It's not merely a reference to any old bible story, it's aimed at the first story: the incepting situation, if you will, of our entire culture.
It's not merely a reference to any old bible story, it's aimed at the first story: the incepting situation, if you will, of our entire culture. & if one imagines an answer to the question as “sure, they could have just gone out the back gate & chosen not to play the 'which tree's fruit is symbolic of what' game with God,” then the implication is that it's possible to say, “so can I & I don't want to play.” The implication is that the situation between mankind & God is perhaps imaginary & relative & there's plenty of other ways of characterizing existence & maybe I'd rather choose one not so mired in consequence.
Maybe I'd rather choose “no characterization at all,” or maybe I'd rather choose a story or a set of stories that haven't been dogmatically shoved down throats over the course of history at the tip of a spear & at the lick of a flame. I don't happen to think this is the absolutely wisest of reasons to reject a set of stories but I won't deny that historical misuse is a real problem for Christians in an evangelical sense. I don't totally blame folks for observing atrocious miscarriages of the word, as well as insinuations (closer to your point) that Genesis, for instance, can be read as a science book, & concluding that there's nothing for them in this mythology. I don't blame them for wondering “could Adam & Eve have simply left? & if so, me too.”
Of course, there's a foundational problem in the personal version of the question. It begins in a feeling of resistance to the whole of (let's say Western) culture & imagines a kind of time travel solution to the whole thing. “I'll just travel back to a point before the fall & give God the slip.” Which, if you watch time travel movies, you'll know just leads to impossible paradoxes that absolutely never stand up to scrutiny. You can't slip out of the garden because you already didn't do that. That is to say, Genesis already serves as the inciting story for a set of stories that already lay at the foundation of culture. The answer to the question of whether or not we can presuppose the foundation is “no, absolutely not.”