I highly doubt that these plans would rise to the chief executive level. The details have been worked out much lower down, and Japan’s plan for evacuating her citizens is totally separate from the U.S. plans for evacuating hers. This is probably meant to create tensions in South Korea ahead of Trump’s visit.
It would be true that Trump and Abe did not spend their time working on evac plan details. I doubt that the message is just for S. Korea, though.