@Flatzone I agree with your list just talking about who is the most naturally powerful Hokage.
Regarding the OP's other question though, about how they'd fare against each other, that becomes interesting.
I'd say Tsunade is the only Hokage Kakashi could beat, but it'd be a really hard fight. Her summon would naturally be weak to Kakashi, since slugs are mostly comprised of water which naturally conducts electrcity. And in general, Kakashi fights in a more cunning manner, so I believe he'd take the slight majority over her with his versatility and assassination tactics.
I can see Hashirama vs Hiruzen going either way tbh. I doubt Hiruzen had Hashirama's power, but Hiruzen is almost certainly far more versatile, with power to back it up. In his prime, I imagine Hiruzen was basically man with the versatility of Kakashi with the chakra quantities and ideals of Naruto. Dangerous combo, even for Hashirama.
Minato vs Tobirama is also a toss-up for me. Minato obviously has the upper hand with FTG, and he spams it in ways Tobirama never did. But Tobirama is more versatile and has more power, which makes up for that gap imo. And while both are very cunning, Tobirama strikes me as the one who would go further to win by any means necessary. I think Minato would win most sparring matches, but Tobirama would win more battles to the death.