I really doubt it.
First off, it's heavily implied that Joyboy had the same fruit as luffy. Luffy and Joyboy (plus maybe one more) are the only ones who have awakened the fruit.
Second, Enies lobby WAS NOT destroyed by the same weapon. It was a buster call, not the mother frame.
Third, it's extremely unlikely that Luffy is gonna need to find some random fruit to have someone else do the actual saving of the world. That would be like I'd Luffy just started beating second in commands while Zoro took out the big boys.
Fourth, it is not likely that Akainu knows the plans, or about Imu. Given how he is questioning his job already, this does not seem likely. Although I could see him switching sides later if he does find out.
Personally, I think that the rising water level is Imus power because Imu is the exact opposite of Luffy, Joyboy, and is opposed to the will of D. It would make sense, considering that he called for a purge along with the water levels going up. It might take him a while to actually start ending things. Also it makes sense that he would have the opposite of a devil fruit.
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