I really believe that the MUTO file should include that the male has some swimming capabilities because it was able to get to the Akula deep in the ocean and taking to the Hawaiian jungle and then taking down a ship that had the armed warhead in San Francisco Bay.
I was looking on Amazon and I found a PS2 game with the Japanese title of Godzilla Kaijuu Dairansen: Chikyuu Saishuu Kessen. I don't know if we have an article for it, or if we have it under and English name. Here is the Amazon link: 
Here's Goji, Gigan, Mothra, and Titano out of package. I can't tell if the green Goji in this image is the same one as the one in your image with the figures in packaging. Maybe it just looks gray in the image but it's actually green?
Also, here's a little bit of a higher quality image of Goji, JJ, MG1, and Hedo
I also know that the figures were released in waves. Series 01 is the one with Gigan and Series 02 is the one with MG1. If we do make a page we can set it up similar to the Sofubi Collection page.