Well, I disagree.
Whole Imu idea is Skypia reference.
Both has
PROMISE to each other to meet again. And the Mural stated they
WILL MEET AGAIN
Trolling and banter aside, it simply does not matter.
Oda could have had all of this planned out with the very first chapter or in the early stages. But as it's coming out right now it gives that feeling of plagiarism.
We can't for sure know if he had it planned or not.
Oda's angels will say yes, Oda's detractors will say no.
But the very fact that's it coming out so late into the story makes it subject to those critiques.
That's what happens when you drag out your story with unnecessary filler and bloated arcs and characters.