User blog comment:ShodaiMeestonLarva/"Godzilla vs. Kamacuras" and "Godzilla vs. Bagan": Real or False?/@comment-831485-20150802101307/@comment-25285745-20150802164716

No, Godzilla vs. Megaguirus was always going to follow Godzilla 2000, it's just that Shusuke Kaneko began planning for his 2001 Godzilla film before Godzilla vs. Megaguirus was fully announced. Once it was, Kaneko decided to not use Kamacuras since the film before his would be using insect kaiju.

Also, the only legitimate source I've seen for Godzilla vs. Bagan is an interview with Takao Okawara, where he says that he heard that Godzilla vs. Bagan was being considered prior to Godzilla vs. Destoroyah, but that he knew nothing specific about it.