Well here's the thing, why can he summon the fox in the first place? Because he's trapped in his genjutsu, that's what Minato broke. When he broke it Kurama was set free then got restrained by Kushina.
The summoning is flavor here, what binds 9tails to Obito is genjutsu.
So yeah—the odds of consenting zombies? Not gonna buy it.
The odds are what we already know
Tobirama cannot stop complimenting Minato, man... Lmfaooooooo.
Minato complimented Tobi during the war too, hell he made his jutsu his signature move. Tobi outclasses him in pretty much every category, besides being slightly less versatile in FTG, which shouldn't be a problem considering Tobi knows it in and out.
It doesn't require Tobirama to be stronger if he wins via a sneak attack though, Shikamaru was not stronger than Hidan but was able to beat him through strategy and prep.
Also, Izuna and Madara were never equals lol.
I don't want him to be stronger than Izuna, an equal is more enough to show Tobi's raw talent.
From the person whose translations were used on Fanverse for the Databooks.
I don't about these translations, I always gave Madara the benefit of the doubt and had him slightly above Izuna, but still a near equal is warranted in a case like this.