edo madara: dream battles!
Now that we see a good deal just how nasty and powerful edo madara is, who are some worthy opponents dead or living besides hashirama. The 5 kages are doing everything the can to simply manage the incoming wave if blows madara gives them. Some were already half spent on chakra beforehand. They aren't gaining the upperhand by a longshot.
I have to put itachi and minato as the two most worthy opponents against madara in individual clashes. Naruto and sasuke are still a ways off in maturity, knowledge, wisdom and battle prowess (though both uber sting, lack enough experience).
Minato can theoretically teleport that huge perfect susanoo away from the battle for a period of time and still have enough chakra to calculate his plan of retaliation. He is one of few who could even trade real blows with edo madara but ultimately he wont surpass that rinnegan even with his full set of near godly skills.
Itachi understands the secrets of sharingan and uchiha. He has the insightfulness useful against op jutsu cast by uchiha. His ability to devise tactics and calculate/think ahead is equal to minato, kakashi, and shikamaru. He may not trade blows with madara as well as say minato but he could last longer in a fight because of his privileged knowledge of how strong uchiha fight. He can avoid or counter at least a few edo madara ems and rinnegan jutsus. He would eventually become overwhelmed before he discovers how to exploit ant hidden weakness madara might
I'll even say kabuto. He has a dirty mix of sage and various bloodline tech to inflict a nasty boo boo before he gets cheesed by sharingan yet again.
This is saying much about these three extraordinary individuals that in this particular match-up; puts them on better footing by themselves against madara than the combined efforts of the current kages or even the legendary sannin in their prime as a team. The "when there is a will there is a way" attitude itachi and minato have when plunging into desperately impossible situations is a major factor in their ability to compete against such a godly opponent.
Minato could even force a stalemate strictly depending on his use of sealing and most importantly, his success calling the death God.