Definitely not. Mr Sunshine is purely fictional. It takes inspiration from various sources but doesn't draw directly from any real-life events or people.
I'm not entirely sure as there could be various interpretations. It might refer to a person named Mr Sunshine and his real - life experiences which could involve his journey, his relationships, or his achievements.
Love is a very common theme. Writers often explore different love stories between the characters, whether it's a new romance or a deepening of an existing relationship. Another common theme is adventure. They might take the characters on new adventures outside the scope of the original plot.