i think obito will have a problem with itachi as kamui wont work on him because to do that im sure he will be caught in tsuykiyomi first and jutsu dont really work on nagato im not sure this will be easy nagato has countless jutsu if itachi wasnt around he would have killed bee and naruto easilyItachi is going to have problems with his lack of chakra considering he will be fighting two extremely powerful shinobi, while Nagato can't move on his own which is just begging to be blitzed by Kamui or another quick attack.
Obito has Kamui, his Rinnegan, wood release, and plenty of knowledge on Itachi and Nagato considering they worked under him. Kabuto has DSM and potentially any EDO that he sees as a good match against the two.
Obito and Kabuto take this one, won't be easy but they will
and what will obito do against isanagiKabuto: DSM, Edo tensei, sound 5 techniques, suigestu's hydrafication, uzamaki healing, and jugo's curse seal.
Obito: kurama/Gedo, rikudou no Justu, uchiha kinjustu, Inyouton, Kamui, mokuton, massive Katon, and bijuu powers if 1-7 if counting Gedo mazou.
Vs.
Nagato: Rikudo no Justu
Itachi: Susanoo, tsukyomi, Amatersu, genjustu variant, Katon, and Suiton
Seriously a Obito/Kabuto puts these pawns on a leash.