As you may already have heard, Nihon-Flex, the publisher of Estpolis III (in Japan) went bankrupt in May. This means a Japanese release of the game is somewhat questionable. However, development should continue relatively problem-free until the stages of production where the publisher is needed.
In theory, Nihon-Flex, being the game's [Estpolis III's] publishers, are not necessary for a U.S. release because Natsume has already taken the role of publisher (of Lufia III, the American version). The shaky part is that this is a bit unlikely because if there is no Japanese reaction to the game to observe there may be reservations about porting it over here.
Don't worry, though. This only means that not only is there still time for Estpolis III to pick up a new publisher, but the absence of a Japanese publisher does not make a U.S. release out of the question.