What could be the possible reasons behind the scanning issues in my Mediamonkey library, especially considering that the scanning problem stopped when I was no longer connected to my home WiFi where the Mediamonkey Server is located? Additionally, what could be causing the long hanging time and ...

You can transfer your audio books from your iTunes library to MediaMonkey for Windows and organize them there before copying them to your phone. Since your audio books are in MP3 format, they should be compatible with MediaMonkey for Windows.