1)There are other ways to catch people in genjutsu other than just eye contact, and actually if Itachi had really wanted to he could have put Guy in a genjutsu very very easily. Itachi doesn't require eye contact to use all his genjutsu, just Tsukuyomi.I agree that Kakashi wud win but there are some things i want to point out.
1. Guy wudnt be caught in a genjutsu because he has fought Kakashi many time with his sharingan, even Itachi had to leave and cud not get Guy in a genjutsu, Gai also knows how to fight without looking at his opponents face etc.
2. Guy's gates take chakra?? I didnt know that, i thought it was something more complicated than that.
3. Guy's speed wud be WAY more than Kakashi at 8th gate.
But ya i agree that Kakashi cud pull it off.
2) Guy's gates do take chakra yes, and alot of it. Do you know what the Gates do? They let the user use their max chakra and strength and speed all at once. They don't increase the amount of chakra he has, just the amount they can release at once.
3) Guy's speed would be way faster only when he is using the Gates but since Guy only uses taijutsu there are ways to get around that.