obito and tobirama
lets not be so hasty were talken about 4 almost if not god tier shinobi
when it comes down to it idk if obito is prown to genjutsu but i no for damn sure 2nd isnt
now hashi vs obito very interesting

obito does have senju dna n tell me if im wrong but has shown mokutan.
but hashi will stomp him after a somewhat extended fight where the 1st is trieng to figure out his jutsu and when he does
dun dun dun lol BUT we havnt seen the full extent of the Rinnegan or even his ms for that mattter so if he could pull a susanno or a chibaku tensei out his ass den i think hashi got it.
now after the 2nd gets hit with tsukiyomi which wont be easy mind you the 2nd trained uchiha and set up their police force so you know he knows a few things about them tsukiyomi doesnt knock him out where he can still fight, then itll sort of even it out because itachi is sick [THERE WAS NO HEALTHY ITACHI] and just used a tsukiyomi which we all no takes a huge toll on him. with his s/t which is not known much or all about the limits but were said to be greater than that of minato, now itachi may pull a victory out his ass but i think tobirama would instantly see the fatigue and use all his might to end it right there.
then the final showdown, the 1st and 2nd :O
just by hype i give to the 1st and the fact idnt no squat bout tobiramas s/t jutsus