Because your reroute involved moving to a non-CO partner (AA) you can request Original Routing Credit (ORC) for the original AUS-IAH-LAX flights. I'm not sure if the DEQMs will post or not, but at least you can get the 1x original miles.

With a reroute that stays on CO metal it becomes a bit harder to get the ORC but you might have been eligible to get some money back as channa notes, even though your routing was somewhat circuitous.