Kakashi said itachi was captain of anbu at 13...itach was 18 or 17 in part 1..the akatsuki said it's been 7 years when they all gathered as shown in part 1..as a matter of fact the information is not accurate..and yes if itachi actually didn't have his ms as a kid..please tell me how he takes these guys down
Kid gaara is out of the question
Kid Rock lee with his gates beats him as he has no defense like gaara
Kid sasuke has the curse mark
Kid naruto with his kyuubi
Kid neji takes him down I believe
It's hard to make an accurate conclusion because we haven't seen what he's capable of as a kid
He beats anyone you listed unless you think all of them were Jounin level fighters in part 1.