Thanks for the report. Very nice photos!
The last one is likely a celestial, or "wild iris." See this photo in the Identifying Wildflowers Photo gallery.
http://community.wildflowerhaven.com/photos/identifying_wildflowers/picture546.aspx
Have you tried Zilker Park? There used to be a native plant garden there and trails where I remember wildflowers growing.
Also, have you ventured down US 71 toward La Grange?