Yes definitely replace sakura with Karin or Shizune you c*e ur mains standard as a heal with the healing tips passive, with Karin doing the same u will have constant passive healing that with do wonders for u. water dragon just as your chase and super shark bomb as your main attack will chain a combo with the main karin and hinata. You might wanna try out shikamaru your last youll b able to chase down the knock downs that your team will end combos with. But with the roster u have rn ur best bet is to run a more defensive build that uses poison damage racking up as a strat.

You can even run hinata shizune karin and ur main for maxium stallyness hahaha
GL