They had to make sure not to kill Kabuto and be able to control him to release Edo Tensei. This thread is a full on fight, no holding back.
False. (I'll provide the same amount of explanation as you did!

)
True.
Kabuto held back on Sasuke since he couldn't kill him, and Itachi was an Edo (which is what saved him in the end).
Susanoo can be countered by the White Rage Technique, or more preferably Muki Tensei to shoot spikes up their Susanoo's since Orochimaru will also be affected by White Rage, but it's still a possiblity.
Amaterasu is countered by either of the two's Oral Rebirth, and Kabuto can just liquefy to avoid it.
Kabuto has already shown his counter for Genjutsu, Orochimaru can summon Manda to avoid eye contact while riding on top of it.
Izanami is the sole reason they won the fight against Kabuto, Itachi was an Edo, which let him regenerate after Kabuto bisected him.
Sasuke killed manda and itachi sealed the 8-heads snakes of orochimaru. Itachi has smartness and sasuke has power.
Correction: Deidara's explosion killed Manda, and Orochimaru can simply avoid using that until Itachi is taken care of by Kabuto.
And since Edo Tensei was included, Kabuto can stomp low diff. (But since that doesn't lead to a debate, I will stick with my current argument).