If you read closely, Frederick almost always gets the idea to stay a woman from the player character. The way I read him is that he's interested in experiencing new things, which is why he enjoys being a woman so much. The group dynamic and how he's not the bravest soul means that he wouldn't want to be the only woman, so he "volunteers" to help when the player character stays. In the hidden ending, partially just to switch up the regular way things go, partially because like the player character he views staying a woman as still being kitsune influenced so he returns to normal because that's what he expects the player character to do. (Not that being a woman is necessarily kitsune influenced, but that's how things were vibing.)
Rpg maker game has been out sadly. It's the research tower one, with all the hardening content. It sucks. I know it sucks. But I woke up with a plan to make a game, and by god I made it. Anyway there needs to be a lot more writing to fill out the blank spots in the design, so I'm making it a writing challenge to get into the swing of writing lots. Also need to redo some of the puzzles.
The visual novel is currently just a retelling of most of the ant paths. The art and music are all placeholder. But the MC has a sprite. The writing is a touch stronger because it's first person and I gave it an editing pass. It's far from essential. A good friend of mine, Salty Justice was adding visual novel functionality to their game engine and offer to help me set up it. Lot more work than I was expecting sadly. I'd really like to finish it someday, but I'll have to finish the twine game first. Gotta get my life's work done.