So you think that Madara could choose to crush a person with fire. :|
I'd say she probably can coat her arms in chakra or something, and then swing her arms at a very fast motion.
This means she should be able to redirect most ninjutsu thrown at her.
It also could be just the mere speed of the movement.
Well if she can deflect them like that, If Large enough i don't see why not.
Plausible but if she did coat her arms in chakra i doubt she would've taken that much damage if any at all.
I Highly doubt it's mere speed of movement, She has never shown such movement before or since.
Itachi's arm got caught IN one of those fireballs.
The actual flames of the jutsu seems to be around the sides of the jutsu, While the frontal part of the jutsu seems to be the solid part, Otherwise i doubt it wouldn't so easily of broken through the roof.
Besides, how could have Tsunade known that "Hey! These are the solid fireballs! The only kind I can block!

DDDD :d d.d
Same happened in DBZ, Some energy waves could be Pushed, Punched, Kicked away, While others not.
All i can say is, Either the users have controll over this when they mold their chakra (or in DBZ's case Ki) or it's just manga/plot logic.