Many of the chararcters Dante encounters in the cantos you mention are his political enemies from Florence.  The main page for the summary on enotes lists a circle by circle summary of who is in each summary; however, if you go to the specific circle summaries you will find a more detailed listing of the characters in the cantos, why they are there, and how they are being punished.  I have provided a link for the first canto that you mention.  I think all the information you need, you will find in the canto summaries.