wow its good, and there is we should find icon anbu and hokage too, if not same like really event its not work

The practice wouldn't necessarily be true to the event.

without Hokage and Anbu support you wouldn't gauge damage or know how effective a team can be.
It'll be empty practice.

Why not? Those just buff stats. The effectiveness of a team is only in comparison to other teams a person can make, with all other things equal. Since none of the teams would have the buffs you would know which would do more damage, and that wouldn't change with the buffs. Also the buffs could be allowed in the practice, for free obviously. Even without them it would give you a good idea on which of your teams would do the most damage.

As nice as that would be, seems like quite a bit of a waste of time since people have already found the highest way to do damage to nine tails for each class. Although I promote being unique, it's situations like these where it's fine to copy others.

I don't know why that would matter as a team that does more damage without buffs will obviously still do more damage with buffs.

That doesn't matter as not everyone has the same ninjas, not everyone can make a team with WB Asuma, Iruka, Sage Naruto, 1st Hokage, etc. Additionally not everyone levels up the same characters so it is really independent on how teams will perform. Having to test new team or passives in the actual event wastes time and leads to less rewards.

Well then how about a damage statistics after the nine tails fight ? You know not just those % total damage.

The one thing buff might affect is shield/confidence(wind blade asuma)
if w/o buff, your shield breaks before the end, you might do lower damage than expected, because you lose the confidence buff.
other than that, I do believe buff will affect all teams equally.

What is really troubling is the effect of mood and awaken can have, because it's unrealistic for one to have all potential ninjas mooded and max awakened (awaken mat at higher level is difficult, due to large requirement), which means your existing "polished" team with mood and max awaken might do more damage because of those factors as opposed to the team being superior. Of course, if the damage increase is minor (say from 0.40% to 0.40001% damage per attack), maybe it's not worth switching due to the investment already made, but a clearer view of exactly how much better a team is compared to another is very important.