What happiness did each character find at the end of the day in The Tale of Despereaux?

Your question works so well with the beginning of the very
last chapter of this wonderful novel:

readability="7">

But the question you want answered, I know, is
did they live happily ever after?

Yes ... and
no.

That is the exact (albeit
general) answer.  However, now allow me to give you a few more specifics about the main
characters.  To make it as simple as possible, I'll use a 1-10 happiness scale (with 1
being despair and 10 being bliss):

ROSCURO (7 on the
Happiness Scale):  All Roscuro ever wanted was light.  He achieves light at the end of
the story, ... with a twist.  "He was allowed to go back and forth from the darkness to
the light.  But, alas, he never really belonged in either place."  He also gets an extra
"happy point" for managing "to shed some small light, some happiness into another
life."  Roscuro tells the princess about the prisoner and allows that prisoner to be
united with his daughter:  Miggery Sow.

MIGGERY SOW (7 on
the Happiness Scale):  All she ever wanted was to be a princess (and eventually, all she
ever wanted was her "Ma").  Mig never gets either of those things.  However, she does
get her dad who "treated her like [a princess] for the rest of his
days."

PRINCESS PEA (7 on the Happiness Scale):  Due to the
loss of her mom, the queen, Princess Pea cannot be put above a 7.  (The princess, of
course, has all of her mental capacity, unlike poor Mig.)  She does, however, gain a
wonderful friend:  Despereaux.

DESPEREAUX (7 on the
Happiness Scale):  Due to the fact that Despereaux is and always will be in love with
Princess Pea, but cannot marry her, he can't achieve more than a 7 on the Happiness
Scale.  "Even in a world as strange as this one, a mouse and a princess cannot marry.
But, reader, they can be friends.  And they were.  Together, they had many
adventures."

I truly adore the complexities of your
question.  Why?  It allows you, the reader, to truly think critically about the
characters and ascertain exactly how happy they become.  "Did they live happily ever
after?   Yes ... and no."  That translates to a 7 on the scale for all of them.  You
see, "happily ever after" implies living in bliss: a perfect 10.  None of our main
characters live in bliss.  Does anyone?