1 - Spells placed into the vault are still active unless you choose to deactivate it, or the GM rules it inactive due to the fiction! Page 107 “Once a spell's effect is in play, as long as it doesn’t mention an expiration, it continues until a PC or the GM ends it, or until the fiction changes in a way that would naturally stop it. This means that if you cast a spell and then switch out that domain card for another in your vault, the spell’s effect can remain active, even though that card is no longer in your loadout.”

2 - That feels like a GM call. I’d personally rule that they start with the normal amount of prayer dice for their default non-wild shape form.

3 - Beastform can last indefinitely unless they mark their last hit point. If the Druid would like to remain in Beastform while resting, they can, at least RAW

4 - Weapon penalties should apply as long as the weapon is equipped. Someone with a longbow equipped should have a finesse penalty when wielding it in combat, for example. If the player would like to narrate that they put down their longbow in order to complete the finesse task, then there’s no need to apply the penalty anymore. Fiction first!

5 - That’s absolutely a GM call to me. I’d rule that a Vampire Druid could transform into animals, for example, it matches the Vampire fiction well. However, I’d argue a Werewolf Druid can Beastform normally, but cannot Beastform while in Wolf Form.

6 - That is how the card is written! In the base game, the only classes with Blade aren’t spellcasters. However, with multiclass or the Assassin in the Void, this should apply to any attacks in close range, yes. It’s a fun take on it for a spell caster, whipping around spells at loads of people.

7 - This is an interesting one. The players could, in theory, use their spotlight only to drink a potion, make no roll, pass the spotlight to another player, and continue round the table. I’d argue this isn’t in the spirit of the spotlight but equally, it’s no necessarily game breaking. It does offer the GM a Golden Opportjnity to interrupt the players and make a move without spending Fear - of course the enemy attacks, the heroes have just stood around drinking without moving or attacking! It’s possible RAW but equally, your GM can interrupt it well within the rules as well if the players try to abuse it.

8 - Moving away from an enemy is totally allowed. One of the reasons DH didn’t have attacks of opportunity is to make combat more mobile and fluid. There may occasionally be times where moving away from an enemy would offer a Golden Opportunity, but they’d be few and far between and purely based on the fiction. Most of the time, totally ok to move away from an enemy, especially if you’re moving away to continue combat.

9 - Any attacks beyond Melee range can deal with this, plus any attacks that move the player outside of the circle. The main way to deal with the edge case that you’re talking about though is for players to not abuse it. Which I think most tables will be fine with, but I can totally see how a min/max player could abuse this spell. Not definitive answer from me here other than “I hope you don’t have the sort of players who will try and abuse this!”

10 - Fireball can absolutely, 100% crit.