Two questions:

First: For Fire main's updated passive, is it really that after he does his first move of the round, the rest of the team just gains a flat 4% ninjutsu increase at that moment? I'm pretty sure it's actually that after this skill is activated, every time ninjas in your team cause ninjutsu damage they get the 4% nin scale. So they have to cause dmg, but if they do a lot of hits that round it can actually be better than just 4% one time at the moment Fire main triggered the skill that round. I saw this happen while using AC Deidara in Infinite Illusion.

Second: So does Madara gain 20% res and def every time he activates his barrier, or does that only happen when his barrier activates and cancels shields he had on him? Because I think it was that way in CN (every time he canceled shields), and since the descriptions in EN often lack information that is actually in the game, I just wanna confirm this. Like, for example, if it was when he canceled shields, it might make sense to run Earth Main with ETR Madara (before it didn't make much sense because you would poison yourself by using his mystery 3) because you could use Madara's passive 1 Y form, set up Earth main's shields with mystery 3 at the start of the round (or use his passive that gives the team shields at the start of the battle), wait for Madara to get hit and then activate his barrier at 95% health, cancel the shields, and then get the resistance buff. But if it doesn't need the shields then sadly there is still no reason to use Earth main with him.