I believe it would be a lot closer than people are writing it off to be; but it greatly depends on the situation. If its same universe EDO Madara then he can control Obito and the White Zetsus, also Negato's eyes are his, so he probably knows the abilities of them. If Madara cannot control Obito and the Zetsus then in this situation, it would be a fairly close fight.
You also, forgot about Orochimaru, as he was a member for a short period of time, but this would be pre invasion, so he would still have his hands, but wouldn't be nearly as powerful as he is now with a Zetsu body.
All the members of Akatsuki are fairly powerful, except Hidan as he would be relatively useless in this battle. If Obito can manage to throw one of them into his dimension, giving the others an opportunity to fight the remaining member solo, then it would be a lot closer. Otherwise, I don't think it would be very close. It really comes down to how well Akatsuki members are able to work together. Nagato, Itachi, Kakuzu, Sasori, Orochimaru, and Obito are very good tacticians. The problem arises that Obito was telling the top members of Akatsuki that he was Madara, but now there is a EDO version of Madara fighting against them. The level of respect and fear that Obito held over the top members would drastically decrease when they realize that he wasn't actually Madara, their ability to overcome that could be difficult. Also, a lot of the members don't work well together. Kakuzu is a very big loner that gets his partners killed, which is why they placed him with Hidan. Orochimaru and Itachi hate each other. While Nagato ruled through secrecy. Deidara is extremely powerful and underrated but he just blows himself up.
Madara, by himself would be able to take on Akatsuki if they were not able to work together. He would be able to take apart many of the lower tier characters with ease, while isolating the more powerful ones. If Akatsuki are able to work together, and Madara does not have full control over the Zetsus then I believe that Akatsuki would win. By including Hashi, then the battle is fairly one sided, but I think it would be a lot closer than people are giving Atatsuki credit. I think Hashi would be sealed, but Madara would not be.
Realistically, have to put too many barriers onto Madara so that he doesn't solo them. Its a very close fight, and would be sweet to see but I have to give it to Madara and Hashi without too much problems. If Hashi was not involved then it would be Akatsuki if they were able to work together.
