1. taijutsu doesnt need chakra as lee cant use it. taijutsu is hand to hand combat which basic forms require no chakra.
2. see you stated me correctly in saying sasuke needed to train to use chidori right but also it was taught to him because of sharingan so that kinda invalidates that statement.
3.kakashi has low chakra reserves yet hes able to use jutsu like raikiri and kamui multiple times and other jutsu and when he died he died of chakra exhaustion, but how do you know itachi died from stamina fatigue? lee was worn out from using the gates but he didnt die? itachi transfered amaterasu and MS to sasuke and im sure that requires chakra so that would mean he died of chakra depletion right?
1. i'm pretty sure the5th gatesuse chakra
2. the sharingan is what help keep up with lee's speed, while sasuke cpied the fighting style and trained to up his speed and stamina
3. Kakashi died from lose of chakra after using kumai a ninjustu that requires a sh*t load of chakra, no stamina. Itaxhi had fairely low stamina
to begin with, and since itachi fought sasuke without his medicine to prolong his life, susanoo, which consumes his life force killed him.
If he use his medicine or had full health that didn't restrict him physically, itachi's staminsa would shoot up to a 5 in the rank book