Naruto is gonna feel that power cap pretty hard, but it won't stop him from doing something stupid like making a ton of shadow clones if he has to do something. It's Naruto. But I don't know what or when or how, and I'm pretty open to anything for the guy. Other than that, he might just keep close to his comrades and make sure everything's okay. Knowing him, he'll also be out and about more than being in his own apartment.

Ragna will probably juts try to stay out of the way, keep things calm at his house, and keep an eye HAHA on any close friends throughout all of it. But mostly keep a hands-off approach to all the stuff going on. I am toying with the idea of having an NPC be some sort of vigilante who might recognize his face, though.

Spider-Man will definitely be trying to do the whole Spider-Man thing on accelerate while this is going on. Trying to keep tensions low, help out anyone, and even giving out his own food when rationing starts up. Of course, he'll be having issues being quite as Spider-like with the power cap up like that, but he'll manage.

As for actually going around as Peter Parker, he'll be looking out to help where he can when he's not in costume. Which might not be often. Other than that, there's not much I can think of for him.