It looks like I can pull it off, but it requires a few role changes. Christian becomes an overly self-assured gay crown prince; Joseph and his mother live in South Haven (the worst of the havens); Paul becomes a background character, good for a few scenes; Andrew is Joseph's best friend who gets killed off early; Adam & Eve are unchanged.
In v2, Joseph's travelling companion bounced back and forth between Paul and Christian for story reasons. In v3, I can have Joseph and Christian together the whole time. I'll need a way to get Christian down to South Haven where Joseph lives, minus the royal security guards. Kidnapping? Also, Christian needs to forgive Joseph for the video that the media say provoked the riots that killed the queen. They then take off together on the slaver.
Voila? This book is going to be ten years in the making.