Kakashi with and without knowledge can't beat itachi.. he even said that...Naruto (now), Madara, maybe Hashirama (if we go by hype), Minato (he gains knowledge during fights). I think Kakashi has the smallest it chances but very low (both him and Itachi are equally smart in my opinion). And if course Nagato (as much as I hate to say it).
Without knowledge would end up the same as part 1.. he goes up to itachi not knowing about tsukyomi or amaterasu, gets put down..