He'd probably be shocked. I mean, a tank is so out of place in the Naruto world. He might be scared too, not knowing what this huge, metal thing can do.
Naruto is a very curious character. So when he finds the tank in the fanfic, he would be full of questions. He'd wonder where it came from, who made it, and what it's used for. He might even try to drag it back to the village to show it to everyone. His friends would probably be just as curious, and they'd all gather around it, trying to come up with explanations. And Naruto would be the one in the middle, trying to figure out how to make it work or at least understand it better.
Naruto would likely approach the tank with caution. He's brave but not stupid. He'd probably circle around it, looking for any signs of danger or any way to figure out what it is. Then he might try to use his chakra to sense if there's any energy coming from it. If it doesn't seem immediately dangerous, he might get closer and start examining it more closely, like touching the metal and trying to find out how it's made.
Clint would probably first be in a state of disbelief. His eyes would widen and he might take a step back. Then, as the reality sinks in, he'd break into a huge grin and rush to Coulson's side, giving him a big hug. He'd likely start asking a million questions about how Coulson survived.
At first, Naruto's eyes would widen in surprise. He'd pick up the fanfiction, not really knowing what he's getting into. As he starts to read, he'd be constantly muttering things like 'What the heck?' and 'This is so strange!'. He might try to find someone to explain it to him, but if no one could, he'd likely just shrug it off as something he doesn't need to understand.
He probably gets very worried. Kakashi is Naruto's teacher and mentor, so he'd likely be immediately concerned and rush to Naruto's side to assess the situation.
Naruto would be cautious. He's been through a lot in his life, and he knows that powerful items often come with a price. He might start to investigate where the blades came from and what their purpose is. He'd also be thinking about how to keep them safe from his enemies. He doesn't want these blades to fall into the wrong hands. So, he'd be on high alert while also being intrigued by the potential power they hold.
He is probably very excited. Naruto has always been eager to learn new things and become stronger. Finding an Uzumaki scroll means he has the chance to discover something unique about his own clan, so he would be filled with anticipation.
Naruto is often full of surprises. He might first act all nonchalant and say it's just a new thing he's trying. But when he sees Anko's serious face, he would start to panic a bit. He could try to make a joke out of it, like 'Hey, Anko - san, this fanfiction - drink is supposed to make me write better ninja stories!'. In the end, if Anko doesn't buy his story, he would probably just bow his head and admit it was a stupid idea.
Snape would likely be shocked and then enraged. Harry is supposed to be the hero of the wizarding world, and seeing him drunk would be a huge disappointment. He would most likely drag Harry to his office, lecture him about propriety and the expectations placed on him as a wizard, and probably assign some form of punishment like a long detention. But as he observes Harry more closely during this time, he might start to wonder what drove Harry to this and if there are deeper issues that need to be addressed.
Naruto would probably be very kind and protective. He knows what it's like to be alone as a child, so he'd do his best to make the child feel safe and loved.
The story in the 'naruto finds a tank fanfic' could also take a more comical turn. Naruto could accidentally set off some alarm on the tank and then start panicking, thinking it's about to attack him. Or he might mistake the tank for a really big and strange animal and start trying to communicate with it in his own Naruto - like way, which would be really funny to read.
He would be very angry. Naruto is not one to take betrayal lightly.