Yep, had all that in my head and thank you for being sure.....I just took a look at the US Customs and Border Patrol website that gives wait times for Border Patrol/Passport Control and for Austin over the last week or so it shows very few non US citizens waiting more than maybe 20 minutes. That would seem to mesh wth Southwest's idea that it can be done in 2 hrs. There aren't any decent AA flights for this itinerary. By the way, the Candlewood Suites is brand new and has some rooms at about $115 pn. Might book one and call it an insurance premium! .

Southwest will book their lowest fare and, if you have to cancel even last minute, will apply the fare to another ticket so that's better than sacrificing it all.