Actually the Japanese version of the game refutes your analysis on Isshu/ Unova. Soryuu city is based on the Chinese allusion, Yacon is based on a plant, and Raimon city is based on the weather and art. Therefore viewing Isshu in the Japanese lens reveals that Isshu's city names are based on human feelings, allusions, and actions that humans committ. Moreover they are based on climate, and geographical surroundings.