Star Wars: The Clone Wars

No. Damage is not tracked between actions, so you must deal all the damage needed to remove a blockade or villain in a single attack. Blockades require 2 damage, while a villain’s health is shown on its sheet (p. 5).

Yes. Any number of Jedi on the mission planet may contribute squad cards by exhausting cards of the types shown on the mission; the cards’ effects do not matter. The total successes must meet or exceed the requirement in one attempt (p. 6).

Before the finale, no: you cannot attempt a mission on a planet with a blockade or villain. A blockade also prevents Jedi from affecting missions, droids, or villains on that planet in any way (pp. 6, 8).

During an attack, you suffer 1 damage for each remaining enemy on your planet and each damage icon rolled; during a mission attempt, you suffer damage from the applicable hazards. Each damage discards one squad card from your hand, and armor cards can prevent damage (pp. 5–7).

Yes, you may reinforce at the seven-card hand limit, but if you ever have more than seven cards, you must play ally cards or discard cards until you have seven. The hand limit applies at all times (pp. 5, 7, 10).