The bit about foreign embassies disbanding makes no sense. Even without contact with their countries, they are still needed to organize all of their citizens currently in Japan, especially the short-term tourists that did not come with enough money or arranged food and shelter for more than a few days.
Patiently waiting months to meet with the Empire leaders is nonsense, after being toyed around for a week they should've just made a showy demonstration using a jet delivering a phone and a message that their emperor is free to request an audience with them at his leisure, then left.
A sentient talking dragon, how nice! Japan should've scoured the world with surveillance drones, found out about them and invited them or met with them a long time ago.