I'll let the experts repyly to the rest of the questions, as I don't use AA's FFP.

Earning Asia Miles by CC in the US is tough, conversion rates are terrible everywhere except the Starwood Amex. The Ebay rates are the next best thing (at least during the double miles promo)

It's too bad there isnt a way to register for the Citibank CX card in HK (for US residents) The card offers 1 mile per dollar for spending in HK & China , but offers 2 miles per dollar for spending everywhere else! If you were able to get this card as a US resident it would probably be the ultimate miles card (exchange rates?) however the only way to get it is if you know someone in HK who has a credit rating they will allow you to use, or if you live/work there.