is there any true goodnes displayed by Alex, or any of the other main characters in the novel?

The only thing I can think of, in this otherwise brutal story, is the ability to exercise free will. That in itself isn't necessarily good but it can serve as the fundamental means to combat autocratic and totalitarian regimes. Check out this GradeSaver link,

http://www.gradesaver.com/a-clockwork-orange/study-guide/major-themes/