For Narita-Osaka-Kyoto-Osaka-KIX, it would not make sense, cheaper to buy individual tickets. Don't forget the Kansai day pass from JR West, which you don't need to buy in advance. That will save you money on the trip from Osaka/Kyoto to KIX.

Buy the Narita-Osaka ticket all together if you are OK not leaving the station at Tokyo or Shinagawa, you'll save a little bit.