Thank you for your question.
I say only the Kansai Thru pass is okay. You can use Kansai Thru Pass for going to Shinsaibashi, Nara Park, Kobe, free pass for Umeda Sky Bldg and other facilities. ( You can walk to Shinsaibashi from Dotonbori though. ) And also transportation between Kansai international airport to Dotonbori by Nankai line.
I hope you will enjoy your trip in Kansai!