...the first part changes everything mayhaps.
The WG is willing to even invade and obliterate an entire Kingdom for Shuri.
This also puts into doubt the entire "WE CANT PROVIDE A TRIBUTE THIS YEAR!" after the fog.
The WG or CDs has no need to destroy the instruments if its about Shuri. They can come anytime and say "Hand her over".
There is no need for this weird fog if they can just come in and crush them either way for Shuri. It serves no purpose for that cause.
And if ifs actually about Shuri all along and they will go to such lengths for her, then it again raises the question, why wait 15 years? They have no qualms about taking babies.
I note they came in after Candel died and if what Growlo says is true then he has been there for a good bit, Brook was just kept away.
Also, Devil Fruits were not known yet or just to Esperia? Because that could definitely mean the fog may be a DF. This is someone's plot and I dont think the WG gains anything from that if they will just march in anyway and they definitelty dont need an excuse to do so either