What you talking about? Read the manga again. She thought Sasuke and Naruto was her sons, then said, "It is indra, and Ashura" Then toward the end he said, "That's bad. Amaterasu is Indra's jutsu" This clearly showed that she was sealed way before they was born and a strong possibility that Indra gave Hagoromo and Hamura a helping hand in stopping her.
She was way more on Guard against Sasuke than Naruto. Clearly she saw Indra as a bigger threat.
I really don't know what to say. You're an idiot.
Indra and Ashura weren't even born when Hagoromo battled the Juubi. Her information came from Black Zetsu (her will).
The part I'm wondering is if you're just ****ing with me or you actually are just that biased towards Sasuke.
I'm not going to argue who is more important over the two in that fight. But to shoot down your theory, Kaguya originally wanted to absorb both of their chakras but tried to kill Naruto because he was too dangerous. He was also the one that mad her lose control over her powers for a brief moment.
As for Sasuke, she already tanked his amaterasu without even breaking a sweat, she destroyed his PS twice already, and managed to get behind him to send him to another dimension (which could easily have been acid or just a stab in the back.)