You've made some good points, I'll address them in order:
- It's being made in GBS
- The animal situation is similar to animal crossing, animals that appear as NPC's won't appear as a wild animal, and vice versa, however unbenounced to the player character is that the animals won't be "normal" animals, they will be affected by the dark magic of the cult.
- A map may be possible, it will be constrained to a GameBoy resolution though so it will be very small, siimilar to how pokemon maps are layed out with the town being a few pixels large.
- The sister idea is a good one, with the latest update you can no longer enter the forest straight away and must explore the area around you, however the sister mentioning the town is to the west would be a good additional thing to add.
Thank you for playing my game and giving feedback!