There's no inherent connection. 'Have a Marvelous Day' is a general positive expression, but Marvel Comics refers to a specific entertainment franchise with its own characters and stories. Maybe it could be used in a Marvel-themed context as a kind of fun greeting, but that would be a creative use rather than a direct link.
It's completely fictional. The show's plot and characters were developed by the writers' imagination rather than being based on real-life events or people. But it still manages to capture the audience's attention with its charm and humor.