kakashi without kamui beats obito without kamui and he has already done it in manga
that was PIS due to obito somehow refusing to use his more powerful techniques (flame barrier, chakra chains, wild flame dance). the thing with obito is he can show something briefly then never use it again.
chakra chains needs kamui to get out it from the other dimension
no it doesnt. its produced directly from obitos own body as seen when he restrained the 5 tails
kakashi can counter obito's mouktun's level easily by his speed,lighting jutsus and the ability to increase the speed by opening gates
lightning doesnt defeat mokuton (sasuke vs yamato, it pushed sasukes kusanagi sword back). also gates? kakashi has never been seen using that in battle. and unlike obito, everything kakashi dioes makes him more and more tired. clones halve his chakra. he has a limit of about 4 raikiris.
fire barrier is jutsu which prevent both of enemy and its user from attacking each other,i mean that obito won't be able to attack in this situation
the barrier IS his attack. he doesnt need to do anything else except take a seat and wait for kakashi to die of exhaustion
kakashi can go underground to the other side so that the barrier would be useless
i dont think it'd work. the barrier burns all that it touches so it could melt right through the dimensional blocks. we dont even know if those blocks are soft enough to tunnel through
