Where did the Qunari come from? And for that matter humanity? Thedas, thus far at least, is a continent. One of at least two, and likely more, considering the migration of the Qunari and humanity. From what we know so far only elves and the Fex can be considered native to the known continent.
The humans of Thedas are much like real life humans in that they have a tendency to shape history to suit the powerful so theirs can understandably be permitted a lapse in documenting pre migration history. However the tenacious pragmatism of the Qunari does not allow for such an oversight. Given that the ancient Pyramids in Seharon( or is it Par Vollen, I forget) depict giant horned deities, there appears to have been interaction between humanity and the horn race that now are identified as Qunari or kossith (focus people; semantics are not the topic) prior to the continent we know of in the game.
That, and other pre migration history, is the history I am most interested in learning more about.
Since most of the countries/civs in the DA universe seem to be based not-very-loosely on actual civs (as in - people in Orlais speaking French), I'm going to guess that the Qunari come from someplace similar to the Middle East or Central Asia.
Tevinter is a very good mirror of the Roman Empire - they conquered the Elves (the Greeks) and appropriated a lot of Elvish culture (like the Romans did with Greek culture) even worshiping what are potentially altered aspects of Elven gods. There's a bit of timey wimey time mashing going on, but the Qunari remind me of the Ottoman empire - the Qun has tenets that closely resemble Islam - which conquered most of what remained of the Roman empire and eventually reached as far as the borders of Spain (Antiva/Rivaini) before France pushed them back. So there's that constant struggle between Europe/Christian civilizations and the Turkish/Islamic civilization.
So~ travel beyond Par Vollen and we'll probably find the DA equivalent of the Far East - China, Japan, Korea, India, SE Asia - technologically advanced civilizations that may have driven the Qunari out of their lands (or driven the original Thedosian humans out of their lands) as barbarians.
There's an interesting species issue though - Bioware could potentially end up in a lot of trouble if they do expand the world and make everyone but the Europeans humanoid, but not human. We know for a fact that not all humans are white, but all human culture appears to be Western - which begs the question of how these two questions essentially reconcile themselves without the assumed existence of human cultures beyond what we know of Thedas.
Yes, using conventional astronomy those are correct conclusions.
We don't have reason to believe that conventional astronomy applies within the Dragon Age universe.
While there is magic in DA, most of the world does appear to follow physical/natural laws that apply to our world: seasons change, there's one moon and one sun, time passes, gravity applies, water freezes and ice melts, fire burns, two biological genders, cold poles etc.
More intuitively - not from an epistemology or physics perspective, but from a literary one, we know for a fact that Thedas is basically drawn from our world - it even borrows our own modern languages. Given that origin, it's a fairly logical conclusion to infer that not only the size of the planet and its axis of rotation, but also the general distribution of cultures exist in such a way as to mirror our own world. There's a collision of timelines of course - some parts of Thedas seem to be stuck towards the end of the Roman Empire/Constantinople, some parts seem stuck around the Medieval Era, some parts seem to have moved into the Renaissance, etc. - but all of it is clearly drawn from our own history.
Also, the Fade seems less a physical entity (in the sense of having an existence in terms of physics) and more of a spiritual one. Remember - in DA:I when you're in the Fade you learn that man made things - desks/chairs - still function within the limitations of their intended purpose, while natural things often behave in bizarre and unexpected ways, which implies that the Fade is a place that reflects intent and purpose as opposed to physical nature - the spirit of the thing as opposed to its physical form, so to speak. Dwarves and those who have been cut off from their own spiritual selves also lack or have a weakened connection to the Fade, which further reinforces the idea that the Fade is not a scientific force but a supernatural one - it is not meant to exist as a physical space, but rather as a realm of dreams and intentions.