Well, you can make your own call, and if I were you I’d not worry about XP. There’s plenty of opportunity in Early Access to achieve maximum level without taking particular approaches to these quests.
Personally, on these questions:
(1) In my druid playthrough I convinced Kagha to turn away from the Shadow Druids, which is a viable way of completing the quest. But some druids might equally decide that she is turning against nature by attempting the Rite of Thorns and kill her if they can’t stop her, particularly if they’re not aware of outside influence. Or they might decide she’s right to protect the grove and side with her against the tieflings.
(2) An Owlbear isn’t strictly speaking an animal in the Forgotten Realms and is classed as a monster I believe. So some druids might decide to treat it as an animal and leave it alone, or hearing about the fact it’s been injured might go to try to help it at which point, depending on the dice, they might be forced to kill it in self-defence or just to back off and leave it. Others might see it as unnatural and kill it as a result. With respect to Edowin’s disciples, I’ve always found they hang well back, so I don’t think there’s a chance for a peaceful resolution with the Owlbear that has them die at its hands.
(3) Accepting the quest to steal the idol for Mol does seem a difficult decision for any druid, so personally I would forego that. A druid might decide to steal the idol because they don’t think those particular druids can be trusted with it, but then giving it to either Gale or Mol wouldn’t feel right to me, so I’d just be stuck with it. But again, it’s your RP and you can do whatever you like!