Your team really is fine the way it is. I would probably put your Scarlet Blaze up next to gaara and the have Kakashi and Sasuke right behind them. The reason for this is because both Kakashi and Sasuke are really squishy. Your Scarlet Blaze is kind of squishy too but he'll last longer than the other two. If I had to change anything;

-Consider swapping out Kakashi or Sasuke for a support character like Sakura or even Shizune. (I'd say take out Sasuke at least until he's 3 star)

-As for formation, you can pull off having gaara at the front on top line, Scarlet Blaze right behind him then Kakashi behind him. Put your support next to kakashi. A decent support can normally take hits (Sakura, Shizune, Karin, etc.) but on top of that, Kakashi's water clone will give them a little extra protection.

Shizune doesn't heal as much as Sakura does but she hits just as hard and makes up for overall heals with her poison dot.