Hi Windemere.
Most of your questions will require some looking into, but I can offer this much right now:
You're right on what the terms Player and User usually denote.
However, a "party" is a group of users (as you correctly said, humans with a unique profile currently playing the game) and their associated character.
It's the same entity player can leave or join by using the "leave party" or "kick from party" options when right-clicking on another user's character, and the same entity they implicitly leave when using the Make War option.
The AVATAR tag is indeed used in order to track which character went through character creation, as opposed to the companions, who are recruited later. They're considered the player's "main" character. Code checks that tag explicitly, though, so replacing it isn't really possible. Why do you want to?
As for Lohse's faction, it seems to me that the only reason to know that is so it can be reinstated when she is added to party again.
Last edited by LarIlya; 28/11/17 08:46 AM.