The playwright character, William, is most likely named for William Shakespeare, who penned the play "Romeo and Juliet," upon which this anime is loosely based. He also often quotes lines from Shakespeare's plays, and his own plays share the names and plots of Shakespeare's as well.
When Juliet and Emilia rehearse lines from Willy's play, the lines resemble the actual text of Shakespeare's Romeo and Juliet.
There are characters with names not from the original play, however, these character names can be found in other Shakespeare plays.
There are several Shakespeare plays that involve females cross-dressing.
When Juliet goes to the Rose Ball uninvited, this parallels the original play when Romeo and his friends crash the Capulet's party. The uninvited guest role is reversed but in both cases this is where they are both smitten with each other.