Dante is something of an anomaly here since he was a real person who wrote The Divine Comedy whilst the rest are wholly fictional. In fairness, however, he was the main character in the trilogy.
As well as the primary character. Remember, it is a fictional story where Dante is guided through Hell by the poet Virgil. Although not a fictional character, he is still a literary character all the same.
I assumed it had to be a spelling error and the question required the answer Charles, as in Charles Swann in Marcel Proust's work. Sadly, I was wrong.
In respect of the Truman Capote work, by all means accept the type-in Holly, but to not allow her full name is simply not right. Her full name is Holiday, and she goes by the name of Holly.
While you are right with respect to Ms. Golightly, the reason that I just accept Holly is the same reason that if I asked who the guitar player was for Guns N Roses was, I wouldn't think to accept Saul Hudson. Everyone knows her as Holly, so get over yourself and just type Holly.
In respect of the Truman Capote work, by all means accept the type-in Holly, but to not allow her full name is simply not right. Her full name is Holiday, and she goes by the name of Holly.