Ostoja

No — you may never place a token underneath previously placed tokens, and you cannot place on or under an Animal cube; token placement is final aside from allowed stacking (see stacking rules). (pp.3,7)

Stacks are limited to the shown types: Trees are a green token atop 0–2 brown tokens (height 1–3), Buildings are a red token on top of one token (any color) and score only if surrounded by at least 3 different top-token colors, and Mountains are stacks of 1–3 gray tokens (adjacency affects Mountain scoring). (pp.3,5)

No — each Animal cube placement is final even if the Habitat pattern is later disrupted; you may only place a cube if the Habitat (including required heights) exists and the target token is unoccupied. (pp.4,7)

Yes — once per turn you must take exactly 3 tokens from a single Central board space and then place them on your Personal board. (p.3)

The game ends when the Pouch is empty when you need to refill the Central board, or at the end of a turn when a player has 2 or fewer empty spaces on their Personal board; finish the round so everyone has equal turns, and ties are broken by who placed the most Animal cubes (then shared if still tied). (p.4)

Each Animal card (completed or not) scores the number shown in the topmost space that does not have an Animal cube on it; a card with all cubes still on it scores 0. (p.5)