Immune ninjas don't work. Roshi gets ignited, chaosed etc.

on topic:

i've had a great success with using kabuto, ukon/sakon and kimimaro (you can swap ukon for tayuya, but then other teammates need to have a reliable taijutsu or tai/nin type of dmg for last round sasuke). I've completed it solo with both of those teams, but the fight really is annoying and sometimes one mistake can cost you 5minutes of game.

You should team up with 2 players to get the most group contribution and with mentioned teams, you can even auto it. Today I've been helping my groupmates with sa, i was running mentioned team, one player had water meta team, the other ftp lightning (sasuke, hinata, kimimaro). SA lvl 93, powers 70k and 2x 45~. We passed it on auto as well. Just find a team and you are good to go.