I did it after some time. i started with this thread as base. i replaced iruka with guy. it did not work. However i started changing more when i saw what i could do better. i ended up with: main, neji gai and kakashi. Characters that everybody has. Here i was about 19,5k bp and level 69.
gai | kakashi | neji
x | main | x
3,3,2,3,2
summon: shark (flood dragon is even better but i don't have it)
important note: sasori is NOT immune to debuffs.
important note 2: it's still rng. neji shield is unreliable. if he won't block hidan and kisame in 1st round. try again. there's high chance you'll lose. Combo's each round are also important but with purify boosts it should go without a problem on this part.
1st round: neji -> sasori. sasori gets acu and won't go off in 2nd round. put fight on auto. the moment kakashi clones die your main should use chakra for his mystery. switch auto off.
2nd round: gai -> hidan. then if possible use kakashi to who you want to kill next (preferably hidan/kakuzu or itachi)
3rd round: neji -> kakuzu. At this point itachi should be dead or dying. same with hidan. rest is just a cake walk. use main and kakashi mysteries when possible. wait with guy and neji to interrupt sasori and deidara. hidan should be dead the moment he comes up but you c*e kakashi mystery when you have to make it faster.
I killed all 6 akatsuki without anybody dying and finished mission with 0 deaths. The rest of encounters are just a cake walk so you c*low some of your chars to die near the end and still get all 3 stars.