Ursafar

If Ursafar plays a gold card for its movement, does it count as active for his silver? Does a card need to be used for its primary action to be considered active?

Card text is not applied when performing secondary actions.

For Ursafar, is it only the card that made him Enraged that counts as active for his silver?

Card, or cards.

When using a card to perform a primary action (e.g. Ursafar's Silver or Green), can you copy a movement action to Fast Travel, or replace an attack with Clear? Or does needing to perform the primary action mean you cannot replace it with a secondary action (Fast Travel being defined as secondary)?

Page 10. Repeat section.

For Ursafar's Angry Roar, can the active effect be a card that was played but whose primary action wasn't performed?

If the primary action wasn't performed, that card cannot be "active". See "Resolve your card" on page 7.

If Ursafar uses his red or gold to clear tokens, they don't become active cards for later use with silver, right? Because clear is replacing the attack action?

Clear is a separate secondary action which replaces the attack.

Does Ursafar's blue immediately enrage him, or is that after the card has been resolved?

Page 10 answers this question and many other commonly asked questions. Your specific question is answered in the first sentence.

If an attack card was discarded due to performing a defense action, and a card is then used to perform that attack card's primary action, does the attack card become "active"? (Whether the attack card is active determines whether Ursafar can use his Silver to perform its primary action.)

Yes.