I would argue this fight would be overwhelmingly one sided in favor of orochimaru and jiraiya. Heck, to kakashi and darui vs jiraiya OR orochimaru would be fairer. Orochimaru is a monster, even without his arms he was able put up a fight against 3 tailed naruto and he became a huge snake against itachi. Orochimaru is the sort of ninja that would require an entire ninja squad or more to defeat. Jiraiya is a monster too. Add in hermit mode and perhaps has more firepower than any other ninja in this fight. not to mention that with his little hermit mode he would have the help from ma and pa each of which would be extremely powerful summons.
The way I see it orochimaru and jiraiya have kakashi and darui beat in terms of stamina, strength, speed, jutsu and summons. Kakashi and darui get stomped. Easily.... Seriously, kakashi almost pissed his pants just standing in front of orochimaru in part 1. Not to mention that orochimaru has more lives than a video game character with cheat codes.
I think Jiraiya and Orochimaru will win, but it won't be easy. Of course, it depends on what Orochimaru we're talking about.
And Kakashi stating he stood no chance against Orohcimaru means nothing to me. Orochimaru likely used fear to make Kakashi think that.
So, Kakashi, the observant Shinobi who has never lost his calm in the battle against anyone else loses to Orochimaru out of fear? Pretty unlikely, I'd say.
Jiraiya's hair is the ''key'' in this fight.
And the worst case is, jiraiya has the power to transform kakashi and darui to a frog.
No, I don't think he genuinely feared Orochimaru, but Orochimaru showed off that killing intent or whatever that messed Kakashi's mind. Part II Kakashi shouldn't feel that threatened by him.
Also, am I the only one who thinks Jiraiya can go into Sage Mode without the toads?
Well, as far as part 2 goes kakashi has shown improved stamina and MS as far as new things go. I still don't see how he could match up to a full powered orochimaru though. Snakes coming out of everywhere, poison, body replacement, kusanagi sword, his yamata no orochi transformation (which is not a summon as far as we know)... Orochimaru is a damn powerful ninja and even without his arms he was able to do quite a bit against the 3 tailed naruto even if he was merely stretching limbs and whatnot. How could kakashi fight that if on top of that orochimaru has access to jutsu which he could not use before? I would insist on kakashi and darui vs either orochima or jiraiya being the more appropriate and interesting topics. I don't see any of the techniques darui and kakashi have shown actually killing orochimaru. The idea that a measly chidori or any variation we have seen could even hurt orochimaru is somewhat preposterous at this point.