I'll go first with Itachi vs Kakashi
The winner of this fight would be Itachi and I will explain my reasoning for this
You say that Kakashi chakra levels have gone up during the war but I beg to differ on this point. Kakashi was not really seen for his encounter with the 7 swordsman and we don't know when all the 7 swordsman were sealed. Thus, we can not conclude if he had time to recover his chakra or if he went straight from them to naruto. Also we do not know how long kakashi, naruto, and gai were fighting tobi before kishi showed us the fight. For his chakra levels vs tobi, you have to look at what kakashi was doing during that fight. Kakashi was not even moving before or after he used kamui, he was just standing still because he knew that if he tried to move he would most likely stumble due to him using a lot of chakra. he was able to concentrate due to him not having to worry about tobi attacking him because he had naruto, bee, and gai keeping tobi distracted.
Now on to why Itachi would beat kakashi. Yes, Itachi eye sight was deterioting and it was probably sever, but that did not stop him from being able to fight sasuke. As we know Itachi let sasuke win so we can't really disypher how much of the fight was legit.
Kakshi vs genjustu: This would honestly defeat kakashi and their is really no way he can break out of tsyukomi if caught. You said that kakashi would not fall for the same trick twice but who is to say that Itachi would fall for kakashi's trick twice. Like you said both are very smart.
Kakashi vs amaterastu/susanoo: Kakashi doesn't move nearly as fast as he would need to in order for him to dodge amaterastu, since he would need to avoid Itachi's eyesight. Amaterastu appears wherever the user's eye is looking at instantly. Like I said the only way to avoid is to get out of the user sight, which only two people can do and a possible third(these are people who are alive). Susanoo weapons are of spiritual nature which means they are technically not physical matter.So it is debatable if kakshi could kamui away his spiritual items. Kakashi would probably kill himself if he tried to kamui away susanoo as a whole and if he tried to make a whole in susanoo then he leaves himself wide open for a counter attack, since we have ever seen kakashi use kamui one right after another one(if I am wrong please tell me).
Disadvantage of both moves:
Kamui: Depending on the object kakashi needs to kamui away, he could increase the size depending of kamui. The consequence of doing this is that it requires more chakra and for kakashi this move is already chakra consuming.
Amaterastu, susanoo, tsyukomi: These are Itachi's strongest moves and they all are very chakra consuming.
Now just like Itachi could counter Kakashi's moves, if kakashi plays his cards right he could find a way to counter almost all of Itachi's moves. If we go by in character, do people really believe kakashi would right off the bat try to kamui Itachi? Their is a risk to Kakashi using kamui so more than likely if they ever had the chance to fight against one another again kakashi would fight cautiously. Kakashi is strong but Itachi for me is just stronger
I really wont go into much detail on why sasuke beats kakashi. The reason sasuke beats Kakashi is because pratically he would get overpowered by an incomplete susanoo, blaze release, and sharingan genjustu.
