Mysteries of the New Sun

According to Michael Andre-Driussi's Lexicon Urthus, the following questions are some of those worth exploring:

Who is Severian's mother?

Who is buried in Severian's mausoleum?

Are the Matachin and Witches' Towers somehow related to Jachin and Boaz (pillars at the entrance of the temple of Solomon)?

What is Hethor's real name?

What is the relationship between Jonas and Miles?

What was the commotion at the gate of Nessus (end of book I) all about?