If Itachi and Nagato were to be in Edo Form then yes they win with High Difficulty. Nagato is a way better Rinnegan user than Madara, and Madara's sharingan is better than Itachi's, but Itachi is more skilled with his Sharingan.
Itachi
-Yata's Mirror, shown no weakness, can take a large hit like sasukes lightning, and it seals too
-Tsukuyomi wouldnt be as effective against Madara but it's still a powerful move and if played right could be the game card
-Amatersu, Itachi is capable on spamming it as he did to sasuke, and sasuke spammed it on the kages meaning it was an effective tactic to get the opponent on their feet
-Izanami, Madara's full of himself thinking he's tha shhiitt and strongest so this would be effective on Madara until he admits he's not tha shiit
-Koton, wont be effective at all, Madara's Koton is far beyond Itachi's
-Shuriken/Kunais, decoys, finding blind spots, like shown when Itachi blinded Nagato's summons
-Susanoo, able to shoot shurikens that are deadly but Madara's "Perfect" Susanoo would be on another scale
-Knowledge, he can think and fight at the same time, and when i say think, its on another scale. He finds his opponents weaknesses and takes it down
Nagato
-Chibaku Tensei, madara has no defense to this besides meteors
-Shinra Tensei, big blast good enough to catch Madara off his feet
-Summons, Dogs are the most effective, for it cant be killed unless Nagato's killed, Bird gives him Air Assault, Salamander gives him sneak attacks
-Powers of SPOP, absorbs ninjutsu's the primary one, absorb chakra to heal him and replenish his own chakra, and Deva Paths ability to control gravity with a 5 second cooldown on it, etc.
-Rinnegan, His usage of the rinnegan is far better than Madara's, Madara awakened it shortly before he died, he never got to use it , whereas Nagato had it all his life.
Madara
-Perfect Susanoo, not much on it but his susanoo itself is relitively strong , but perfect? could be better than Sasuke's and Itachi's susanoo together
-Meteor, able to spam them with no trouble
-Koton, Super powerful, Took a number of guys with Water techs to cancell Madara's Koton out
-SPOP, able to use some of the SPOP powers but not sure if he can use all of them.
-Mokuton, Create wood in an instance , able to use wood whenever
-Mokuton Clones, MAdara is able to Spam them and did spam them and Use Susanoo on them.
-Hash's cells, i believe that the word "Perfect Susanoo" is from Hash's cells. Hash gives anyone a good power boost. Tobi's "Perfect Izanagi" Was because he had some hash cells. So who knows what else it gives you.
-Edo, cant be killed only sealed but thats no problem for Itachi or Nagato. Nagato could use gate summon to absorb his soul or Itachi could use Yata's
Itachi and Nagato have more plus's than Madara has. Madara would put a good fight and make it a high difficult win for Itachi and Nagato.
If it were to be a cold-blooded killer that Itachi was when he took out his clan, and Nagato when he nearly took out Bee and Naruto by himself, than Madara would have the hardest time of his life fighting these two and it would be a medium difficult win for Itachi and Nagato. But seemingly thats impossible , Itachi and Nagato are too soft hearted and Madara likes to play around alot, it would be awhile for Madara to go down, making it High Diff