AA miles do expire. Log in the AA freq flyer web site: will show the expiry date.

The US airways miles will convert to AA miles some time in the future. Date is unknown. As is if what will count as an eligable activity in the AA account (US flight, conversion date or ??) Make sure your name & address is exactly the same in both AA & US accounts

Go to each freq flyer web site. Easy to determine how many miles needed for a trip. Some programes allow one way trips and other only returns. Co-payment fee if required is harder to determine

Selling miles/points is against the t&c's of loyality programs