Right, that's set of questions.
1: Why did Hagoromo awaken Rinnegan? Or MS for that matter, since he knew Hamura was in no danger. Why would he get Rinnegan just from being pissed off, when that's not how it works before
While the exection of the scene may have been sloppy, there is indeed logic behind him awakening the Rinnengan. First let's look at the Rinnengan in general. At first they told us you get it with Uchiha+Senju mixture. Well we have that in Hagoromo since both clans carry his DNA. That one's checked.
Then we had Sasuke awaken it with the help of Hagoromo's chakra and a death experience. Since Hagoromo already has the perfect chakra needed to awaken it, all it took was apparently an emotional push towards an MS (which would directly go to Rinnengan as the above mixture is already present) which he gained from two things:
- having to kill his mother who he loves greatly
- having to inflict pain on his brother who he loves even more
Even if Hamura didn't die, the emotional engagement was serious therefore, the chakra in his brain was undeniably going wild. (which is exactly what we need for progress in ocular powers)
2: What about White Zetsu? This filler shows the IT fodders getting released, but according to BZ they were absorbed by the Gedo Mazo.
This episode only showed the last wave of people getting released. There has been quite some time since the rituals begun, and the people trapped were used to power the tree. It absorbed them. So, the people from whom these White Zetsus came were all the previous generations sacrificed to the tree.
3: Why didn't Hagoromo use Sage Mode at any point? He never has the obvious eyeshadow.
We didn't really see him fight Kaguya at all tho. We only got a short shot of him in a PS and the only on-screen fight was the one with Hamura, and there was no need to go SM on a brother when you have the main villain to fight after that. (Especially since he spent the tag on reviving his bro.)
4: Indra and Ashura's Mom. Still no identity, since Haori is still dead.
There are other fish in the sea dude. :sdo:
5: Seriously, where did the Yin/Yang Seals come from
The two awakened them much like they did all other jutsues they possess. We don't know much about the seals, besides the fact that Hagoromo gave them to Naruto and Sasuke. If he is able to pass it on to others with no special requirements, I don't see why he couldn't simply mass enough chakra (as the seals are simply a tool for the most powerful CT) and get it naturally.
6: Where did the Gedo Mazo come from?
Gedo is simply Juubi's shell. It was sealed along with Kaguya, and Madara later summoned it after awakening the Rinnengan.
7: Why where the chumps released from IT still alive, when Haori was dead?
Those chumps were unintroduced so it's probable that they simply freed them before it was too late.
Why do all villains get a one off opportunity to paralyse the heroes which they always waste? Seriously, how many evil transformations are accompanied by the hero saying "I Can't Move" or something stupid like that.
Kaguya was taking back their chakra, therefore she needed them alive. Also, she saw her long lost sons in them so it was a greatly emotional moment as even a cold-hearted being like here couldn't help but cry.