haven't read the whole thread but going to reply to the OP
yes hes kage material, but he wouldn't easily beat any of the other current kages (i just finished watching the 2nd part of the new anime ep where they show Tkage and mei's jutsus, i thought dust release was totally ****ed up by the anime but cool in the way they made it too) hes not stronger or faster then raikage in his lighting armor (unless you think kakashi thinks and moves faster then minato) sasuke has the same abilites that make kakashi feared and way more (instead of kamui he has susanoo,amaterasu and a weak tsukiyomi) sharingan can't keep up with A's body flicker and sasuke's chidori could barely scratch him thru his lighting armor idk how much more raikiri could do.
Oonoki can fly and use dust release (assuming the one in the manga not the weird molecule disembler thing in the anime) he could blow up wherever they were fighting, seemed like that cone thing he was going to use on deidara was strong enough to destroy the big turtle island (said by his big goofy bodyguard). his back and age would be the massiver turning point since kakashi is young fast and has sharingan he might be able to hit oonoki with genjutsu when hes preping a dust attack and kamui or chidori him (assuming hes not way way up in the air while hes doing it)
Mei has lava and acid mist that could keep kakashi on the D and away from her above ground, but he could go underground and attack her from behind with a chidori (maybe use a clone to distract her above ground till he strikes) it could go either way to me since we don't know her full power.
gaara's defence was only passed by when he was much younger and a genin and a tailed host, idk if his sand has gotten any different since losing shikaku, but kakashi can use atleast the first gate which as kids was enough for lee to get by the sand, might let kakashi get by long enough for a chidori or kamui to srsly wound or kill gaara.
he'd wipe the floor with tsunade imo, i know hes not a real kage but since he was at the summit, with danzo he'd either have to fight with low chakra cost moves, but aggresive enough to keep him using his izanagi till its out or don't let him activate it in the first place.
kakashi could technicly beat anyone but madara and zetsu with a kamui to the head if he was fast enough with it and they didn't have something to passby death like izanagi or space/time