In theory

[Andriy]

Should a noninflected chakra fire hurt(hurt is much to say, but you get the point) a juubi jin? That fire it's natural energy

 

[Motion]

That actually makes sense. But I don't think it works like that.

 

[Gein]

Fire jutsu is just plain old chakra converted into fire.

Natural Energy is more like a life force of the air and earth around.

 

[Seventh Sama]

Nope. V1 juubito tanked a bunch of exploding paper bombs from tobirama. iirc explosions generate alot of heat.