I tend to do something similar to 3, but the joyous whimsy is some sort of twisted reflection of what it should be.
An example of my upcoming book: There is a character that struggles with crippling anxiety when making important choices in their lives, for ~spoiler~ reasons. They simply get locked on themselves when they have to decide on something that might have serious consequences.
The REAL joyous whimsy would be to go through a character arc that makes them stronger, and finally able to think for themselves.
The joyous whimsy I'm giving them is to fall under the wing of another character, who is willing to make their choices for them, at the cost of personal freedom and identity. They eventually begin to accept and even encourage the dynamic. The whimsy has been completed. They are now happier than they have ever been - they no longer have to deal with the stress and fear of making the wrong choice. However, was it for the best? What was the cost?
That kind of stuff. It's not really 2, because at the end of the day, the character does end up happier than they were before the book began. But it is also not a good ending for them.