On Topic:
My hope for backstories in an Antiva/Rivain/Llomeryn setting. My idea is that each can have a playable "Origin" that takes place in the same setting to conserve art assets (I'm thinking Antiva city):
Elf: Just to flip things around, let's make the elf the noble. Antiva's real political power is split between a number of merchant princes, say one of those princes is from an elven family that has fought tooth and nail (With much backstabbing and underhanded dealings) to achieve its position amid human society. We could be one of the children of the family head, thrown into this mess by circumstance and possibly being on the wrong end of a Crow contract. If the PC was a mage, they can say that the family hid it and hired tutors or that the family head sent hirelings to retrieve the PC when the circle rebelled. Alternatively, being an elven member of the Antivan Crows could be interesting, at the risk of retreading Zevran's backstory. I'm not sure what the Crow's stance on recruits that turn out to be mages is though...
Qunari: Going with the idea that a follower of the Qun represents too many problem narratively, how about a prized Tevinter slave? One must remember that Tevinter slavery isn't racial, they take humans, elves, and probably Qunari. This is sort of the Player Character version of the escaped Saarebas idea I mentioned earlier, though to avoid ascribing motivation to the PC, they could have been smuggled out by Tal-Vashoth when they were young or captured by Tevinter when they were older.
Human: I'm of two minds on this, since the elf now covers the noble background, let's have the human be a Raider, somebody that's been at sea most of their life, pirating. Or we could possibly revisit the Antivan Crow angle, but I like the idea of being more or less forced into a raider crew from a young age as a background. It would be new atleast, and fits slightly better with the protagonist possibly being a mage.
Dwarf: I'm assuming Kal Sharok dwarves will be something we get to learn about, not something we get to be. In which case we might revisit the nobility angle and have a Merchant's Guild family background. That puts the dwarf in an interesting place, interacting with both the nobility and the criminal element.