Very informative, thanks for posting this again here, it allowed me to take a fresh look at the progression of the Southwest special liveries. My favorite one is Shamu in the mustard rocket colors as it was the first one I saw back in the mid-nineties during my first visits to Houston. It was always nice to catch the orca flying around the Houston sky lining up for 12R at Hobby. There was a nice model shop in a tourist area of Houston at the time that carried Herpa 1:500s, I got a model of Shamu and the Silver One from them.
Here is a picture I took N334SW in the canyon blue colors landing at Hobby Jul 26, 2012. Probably the last time I saw it. I did not know it was still the original Shamu; after all those years I would have thought the livery had transitioned to another airframe. Very cool it didn't.