I'm going to say Minato and Bee take this high difficulty. FTG versatility and Minato's ability to warp Bijuu Damas will help them take advantage of Shinra Tensei's 5 second interval and land a hit on either one with Bijuu Dama.
Nothing short of focused CST is taking out Killer Bee, and Minato can evade that so Nagato loses Deva powers meaning all he has now is animal summons chakra absorption asura rockets naraka path and human path. Minato will be able to teleport around the battlefield until Itachi drops V4 Susanoo, meaning no Yata Mirror. Without Yata, Minato can mark Susanoo and teleport it away allowing him to kill Itachi with Rasengan and Nagato with FCD. It all depends on if Nagato will regain his Deva powers before Itachi drops V4 Susanoo.
Nagato's animal path will be a useful distraction, he can do his summonings, and that would keep minato and bee very busy.
Nagato also has preta path, so while he isn't blowing away techniques, he can be absorbing them. Itachi has totsuka blade, all he has to do is cut bee as he is the slower of the two and bee gets sealed away.
If nagato uses bansho Tenin on bee and grabs him, then either naraka path or human path kills him, take your pick.
Honestly, bee would be the first person to go, either by itachi's hand or by nagato's, and when that's done, minato goes not long after.