kakashi and gai dont have any way of penetrating susano ribs + enton kagutsuchi. kakashi and gai arent stupid enough to try and physically attack a freaking wall of flames. sasukes seen kamui before so susano arrow + amaterasu shurikens + chidori senbon and kakashi will already be exhausted from the barrage. his only options vs the first two is kamui. sasuke has more powerful genjutsu, more powerful chidori variations, hawk summon and kirin if he needs it. amaterasu (left eye) pretty much incinerates gai as soon as gai slows down. gai would need a relentless hard and fast assault on susano/flame wall. and hed lose an arm or two just getting through to hit sasuke himself.
and do you know how freaking fast sasuke is now? A is pretty much the faster, stronger and more durable version of Gai, only he doesnt have to kill himself to achieve the strongest nintaijutsu. and sasuke survived all his most powerful attacks while only having his susano ribs. and despite all that, sasuke landed a hit on A with chidori. this was supposed to be very impressive.
if kakashi and gai wear him down, sasuke still has enough chakra for hawk summon/chidori senbon barrage to escape and then great dragon fire + kirin to finish things off.
if kakashi tries warping away susano, sasuke will immediately notice and set him on fire.