Replace Tobi with Kakashi :victory:

Stay with Tobi. The most important damage you can do in the nine tails event is elemental. Seeing as Tobi does this, AND he has a revive after the tailed beast bomb, I'd stay with him.
Tenten increases critical hit rate, but she has nothing on Gai.
Gai has op physical damage, but it's always elemental damage that's worth more.

In short, * with Tobi.

Well, Tobi atk grow it's really low, his burst damage proc with his chase but, as you know, you can't chase the 9tails.
For the revive passive.. meh usually you just lose precious time doing another turn fow few damage..

Kakashi it's not fire yep, but he deal elemental damage with both basic and mystery attack plus there is his copy that deal more damage.

So, if you don't have Windblade asuma or Hashirama, kakashi it's the best choice

Thanks for advice man going go with kakashi then.

usually, I use tenten. Her 10-hit chase and the crit boost makes her winner over kakashi or guy.
for a fire main setup, your main is the main damage dealer here. anything that buffs him, goes well. Crit hits are quite important in dealing more dmg to nine tail, so tenten and high level refinement both plays a big part here. Make sure to give best refined gears to your main.

Tobi is fire type, but his standard or mystery doesn't do any elemental. Also, he's not konoha ninja, so doesn't get iruka's buff. And, if you go with anko, iruka, tobi - thats 4 fire ninja. Main's passive can only give buff to 3 ninja, so someone will miss it.
Guy can deal quite a bit of dmg, but doesn't have any 10-hit, and while his small tai buff is quite good- you need mainly nin buff for your main. Iruka is easily a better choice than guy.

Iruka, anko and ten ten with tonton summon