Well, our eyes are like windows to our souls. When someone is angry, their eyes might narrow and seem to glare. In contrast, when a person is in love, their eyes tend to be soft and tender, often lingering on the object of their affection. Also, eyes that are constantly darting around could suggest nervousness or unease.
Toge Inumaki is important too. His special cursed speech ability makes him stand out. Also, the principal of the school, Masamichi Yaga, is likely to be important as he is in a position of authority and has an influence on Gojo and the other students. There could be other characters like the members of different clans that also play roles in the complex web of the story.
His friends would probably be shocked at first. Sasuke might be a bit conflicted, seeing Naruto with an Uchiha - like power. But they would also realize it could be a great advantage for Naruto and for their team as a whole.
His friends would probably be shocked at first. Sasuke might be a bit jealous since the Sharingan is a Uchiha thing. Sakura would be worried about the implications. Kakashi, having had the Sharingan himself, would be more understanding and might try to help Naruto control the new powers.