If you occupy Acadia, you can use the ability as many times as you like on your turn (2 cards = 1 wild, 4 cards = 2 wild ...etc)
The bear piece is simply a 'first player token'. Whoever takes the first turn of the game holds onto the bear until the end of the game is triggered. All players are supposed to get an equal number of turns, and this helps you remember who went first.
Yes. They are also eligible to occupy the major park with their own tent if they haven't already done so.