Do I play Dalish because it's the most interesting to carry forward into DA2?

Interesting.

Well, it's a theory, anyway. I don't know for sure. But because of the connections there, it seems likely.

Now that I know a good deal about the Amell family, my head canon has shifted DA:O Amell and DA:O Surana even further apart as far as how I imagine them acting in game.

Right? It makes sense, at least -- you can give a Surana any of a number of backstories (mine had a reasonably happy childhood in the Alienage), but none of them involve being scion of a semi-disgraced noble family in another country. Although I suspect that this difference wasn't actually planned when DA:O was being written -- it's almost certainly a retcon. But a retcon that I find quite interesting.