You using MB so put lee 8 gate in, work well with leeching passive skill. Try to figure out 3 main strong formation that you use in arena. 3 typical formation that I c*e with tohse ninja you have is:
1. Naruto - Sauke - Hinata (put Tobi in for a 4 ninja ranked battle formation)
2. Neji - Guy - Lee (Lee 8-gate is better, you can put GNW ten ten in for ranked battle)
3. Kimimaro (3star) - Kabuto - Yamato I not sure about this one, You can maximine the efficency of this team by getting Orochimaru in, or any curse mark ninja.
Advise from a F2P player, I always pass all survival stage from the first day the server open.