I would personally choose Earth main (sometimes Fire main) for Roshi
With Utakata, Yagura as the rest

Heres how I usually put it:
x-x-x
Earth main/Fire main - x - Roshi
Yagura - Utakata - x

Talents:
3-3-4-2-3 (Earth main, I hope its the right one) for Fire main = 4-4-3-4-3
Summon:
Gamaken/Gamachu

Sadly, Yagura have pretty low health, and he is important for this team because he can acupuncture and help triggering Roshi's chase
The opponents more likely targeted Yagura because of this

The reason I don't choose the Chameleon summon or any 10 hit chase summon (Fire main) is because I assume the opponent have at least 6 units on their team so it will be a guaranteed to get 30 hit for Roshi (Mystery).. If the opponent have 5 units it only reach 29 hit
that is why I prefer Earth main with his double standard mystery. If you have Higher initiative than your opponent, use it after your opponent's 4th action ninja or clones do their standard, so you can trigger Roshi's 30 hit chase 1st round (If Utakata didn't trigger his chase yet) and 2nd round

But, Earth main Double standard mystery could a problem if you face blitz team, because the placement, Roshi will take lots of damage with no 1st round shield, If your Roshi survive, you will probably win because Earth main mystery will shield Roshi twice and also because he buffed so much after those attacks