SM Naruto War Arc, but not friends with Kurama
Not friends with Kurama means no Toad fusion, so he's stuck with a few FRS and a single Chou FRS. Chou FRS gets Amaterasu, regular FRS get Enton, and Susanoo can tank one if it gets past. Naruto gets mowed down by Susanoo eventually.
MS Itachi His sickness will not have him coughing up blood
Itachi is better than Sasuke in every area, so it comes down to who can hold Susanoo longer, which is probably Sasuke.
Kisame would most likely win if Sasuke ended up trapped in the Water Dome, if Sasuke can get above it or out of the way using his hawk then he can light Kisame up with Kirin, but that isn't likely.
Sasuke wins. Hawk lets him fly above ground level and V4 Susanoo cuts through Gaara's defenses and kills him.
Gai Cannot open the 8th Gate
Gai could win by outlasting V4, however while V4 is up Sasuke can't be touched. So Enton and Katon to heat up the atmosphere and Kirin to end his life.
Refer to canon.
Mu probably outlasts Susanoo and kills Sasuke unless Sasuke uses Kirin to nuke the entire area.
Nagato CST and CT are restricted
Nagato still wins mid diff. Preta Path can absorb Susanoo and the vast majority of his techniques, and the ones that can't be absorbed can be repelled.
Ay and Onoki dance around his Susanoo until it's weak enough for them to put a hole in it like they did Madara's.
SS pounds Susanoo till it breaks.
Killer B probably wins.
V4 Susanoo or Kirin obliterates him.