Madara + Kakashi vs Nagato + Pain + Itachi
Madara- Space time ninjutsu, amazing tactics,and experience over everybody I mean he is like 105 years old. He has the rinnegan too and has his own 6 paths.
He has the EMS, he has summoning of the 9 tailed fox, can control bijuu, and Kakashi is just for support. Madara would take them on hardcore style!!!!:D enuf said....
Kakashi- Just a weak support would be killed easily with deva path but this time he knows the abilities of Pain and maybe just maybe he would be able to kill 1 or 2 paths.
Nagato + Pain- Nagato the one who appeared in the manga with his 6 paths of Pain. This leads to a big advantage but His opponent will be the 9 tailed fox and Madara plus Kakashi it would be one hard battle with Itachi.
Itachi- Very powerful, Genjutsu, Taijutsu, and Ninjutsu plus Dojutsu everything about this guy is just amazing to be looked at. He has never lost a battle in the series but to Sasuke because of illness and plus he let Sasuke kill him. Itachi needed Madara's help though to end the Uchiha, now he will have to fight Madara, Kakashi, 9 tailed fox,but his not alone he has 7 others to fight with him and I guess if Itachi dies he could be brought back to life be the revival path.