Jeez. Let's look at the allies:
- Luffy is cooked. He's actually weaker than Imu thinks because of his time limit and lack of knowledge. Way too many improvements needed to actually win unless Oda's doing his worst.
- Zoro is also at a disadvantage in match up knowledge. Humble Haki experience vs a very experienced guy who can afford to take damage or even just leave if the going gets tough.
- Sanji's powerless against Zaza and out muscled by Killingham. He can't use CoC or rescue the children at this rate unless he gets some help.
- the Straw Hats can probably survive a chapter or two if they don't fight but man, Imu is right there.
- Loki is seriously hurt to the point where he's being protected. Even if he sees a weak spot, he's just too big a target.
- Gaban and Gunko aren't their best and probably have to die to make some impact.
That said, the goals are pretty small. If Zoro cuts the heart of Sommers out, Imu might leave. If Gunko gets in the way and dies, probably the same thing. If Imu really does have a time limit, I'm not sure how they exploit it but altogether they can take a while, or he could just act like any other dumbass villain and declare victory for no reason. It looks like Brook of all people might be relevant. If someone shows up from the outside like Shanks it'd be terrible but the Straw Hats are due for a training arc or something anyway at this point