When you run out of cards to draw, reshuffle the discard pile and resume play. But if you run out of cards again, reshuffle once more, but the game is about to end. The current player completes their turn, each other player takes one turn, and then the winner is the player with the most VPs.

No

Some special effects are powered by discarding the building after it is built. You cannot power a special effect by discarding from your hand.

Yes

Unless a card states otherwise, Wild and Effect cards take effect in the order they are played. When a card gets bonuses, multiplication takes place before addition. So, for instance, a Cavalry card (attack strength 2) would be doubled to 4 if you use The Minstrel on it, and then increased to 5 if you use the power of a Military Stable.

With three players, make these changes: (1) When the Movement Die shows that Groo moves by two towns, he moves only one. (2) Play to 8 VP worth of buildings.

You can have fun with only two players by making these changes: (1) When the Movement Die shows that Groo moves, he always moves to the other town. (2) Play to 10 VP worth of buildings!