Vast: The Crystal Caverns

No. First orient the revealed tile, then fill all new open edges with Dark tiles; only after that do you resolve the tile’s effect. This applies before the Collapse begins (Rulebook, p. 4; FAQ, p. 3).

No. The Knight may move and spend Encounters in any order, but she can move only while she has at least one Encounter remaining. Equipment and other abilities that do not require an Encounter or movement may still be used afterward (Rulebook, p. 6; FAQ, p. 7).

Not before the Collapse: the Knight needs to use a Bomb and may attack only once that turn. During the Collapse, a Bomb is no longer required, and once the Dragon is on the surface he can be attacked multiple times, once per Encounter (Rulebook, p. 7; FAQ, p. 8).

A Tribe can never have more than 4 Population discs. Add enough discs to reach 4, then resolve overpopulation by scattering one Tribe; the scattered Tribe does not have to be the one that exceeded the limit (Rulebook, p. 8; FAQ, p. 11).

The Thief cannot cross walls normally; he must use the Climb action, which costs Action cubes but does not provide movement by itself. Movement and actions may be mixed freely, and he may continue using either one even after the other is depleted (Rulebook, p. 14; FAQ, pp. 17–18).

The Collapse begins at the beginning of the next player’s turn after all Cave tiles have been placed. From then on, open edges are not filled, and the Cave removes three tiles during its Shape the Cave phase; the game ends when five Crystal tiles have been removed (Rulebook, pp. 4, 12; FAQ, p. 3).