It's now all been made clear, thanks to Sherman of the dev team who has shown us the footage that was used to prepare those. Essentially, the team was put in front of the fact they have a spot in Famitsu and they have 10 days to produce some screenshots to accompany the article. At this point it was all hands on deck and personally I think this came out rather well! Clearly the screenshots were then dressed up to make them prettier but at stages as early as this I don't think it's bad practice.
As Sherman explains, Zsolt's art of the Good Future was used as inspiration to try and create the underwater rocks with corals growing on them: