Seems like overall good points. Except -
1. While Minato is still figuring out the clam's genjutsu and how it works, the real Mizukage (whose presence is hidden by the clam's genjutsu
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) can sneak up behind him and snipe him with a water bullet
2. Minato won't be able to effectively tag the Mizukage due to his water body (same technique as Suigetsu's), since the Mizukage can just "shed" that part of his body off by removing the water from the tagged area.
3. Joki Boy can be summoned as a distraction to prevent Minato from focusing on the genjutsu, and rather fight the steam clone. Boss summons can't do much against Joki Boy since it is far too fast for toads to keep up with and its steam explosion either kills or injures them. While Minato is occupied with detecting the clam, Joki Boy can
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limiting the number of places Minato can teleport to, or if Minato chooses to Focus on Joki Boy, the invisible Mizukage scoops up the kunais. Minato's kunai slashes and rasengans probably aren't capable of putting down Joki Boy in any sort of way. Trollkage can also wash away the kunais with his oil. The location is a desert so FTG markings on the sand will be broken apart by the oil once it seeps in through the sand.
4. He can't summon Shima unless he knows about the necessary blood summoning which he must draw on his face and the special summoning ritual needed to summon an Elder Sage, which requires holding his hands together for several minutes.