As for Shikamaru, he'd likely just take it in stride. He'd realize the implications it has for the village and for Naruto's future. He'd probably offer his strategic advice to Naruto, like how to handle the new attention from the village, how to deal with any potential enemies who might target him because of his heritage, and how to use his new status to the best advantage for both himself and Konoha.
Sasuke would have a more complex reaction. He might see Naruto's heritage as something that makes Naruto a worthy rival even more. But at the same time, he could also feel a sense of comradeship knowing that Naruto has such a significant background. They might even train together more often to explore Naruto's new - found abilities.
Sakura might be shocked at first, but then she'd be really happy for Naruto. She'd probably be more protective of him too, especially if there are any threats related to his heritage. After all, she's always cared about him in her own way.
Naruto might initially be confused. He has grown up with a certain view of himself, and this new information about his heritage completely shatters that. He may struggle with his identity for a while, but as he digests the information, he could start to feel a sense of pride. He might think that now he has a greater purpose, something that ties him more closely to his family and the ninja world in general. He may also become more confident in his abilities, knowing that he comes from a great lineage.
Sakura might be initially shocked and heartbroken. She has been Naruto's friend for a long time, and his sudden departure would leave a big hole in her life. She might try to convince him to stay at first.
Sasuke would be extremely enraged. He has a deep bond with Naruto, and Naruto's death would likely send him on a quest for revenge against Konoha. He might see it as a betrayal of everything Naruto stood for and fought for.
Well, one possibility is that the village's attitude towards Naruto would change drastically. They might start to see him as a valuable asset rather than an outcast. People who once shunned him could now be eager to befriend him, thinking of the power and status that comes with being related to his heritage.
Sakura would probably be both amazed and a bit worried. Amazed because Naruto always seems to get into these extraordinary situations, but worried about what new dangers this Lantern Ring might bring. Sasuke, on the other hand, might be initially skeptical. He'd want to see what Naruto could actually do with the ring before he gave any real reaction.
When Naruto's friends see him with the Spartan armor, it would cause a stir. They would all gather around, asking questions. Some would be excited about the new possibilities it presented, while others might be worried about where it came from and if it was dangerous. Naruto would have to explain what he knew about it, and they would all start brainstorming about how they could use it in their future battles or missions. They might also have to deal with any jealousy or envy that could arise if the armor seemed to give Naruto an unfair advantage.
Shikamaru and the others from the Rookie 9 would be shocked. They have always counted on Naruto to be there in Konoha. They would probably feel a sense of loss and also a bit of guilt, wondering if they could have done something to prevent Naruto from getting so tired of the village. They might try to find ways to get him back, while also respecting his decision if he is determined to leave.
Shikamaru would be annoyed at first, thinking that Naruto has gotten them into another troublesome situation. But he would soon realize the potential benefits of having the baby dragon around, like using its abilities for strategic purposes in battles or for the overall protection of the village.
Sasuke would be more aloof about it. He might not show much interest on the surface, but secretly he'd be observing Naruto's every move. If there was something in the base that could help him in his quest for power, he'd definitely be interested.
His village, Konoha, would be in shock. The ninja council would probably gather immediately to discuss this strange phenomenon. Some might think it's a new threat, while others could see it as an opportunity for new knowledge. The villagers would be both scared and curious, looking to Naruto for answers since he was the one who found it.