Originally Posted by Windemere

Specific question related to best practices:
What does CharacterAddToParty() do that isn't impicitly handled by CharacterAssignToUser()?

I have extended the documentation of CharacterAssignToUser and added documentation for CharacterAddToParty. The answer to your question is: nothing, CharacterAddToParty won't do anything extra. I know the Lohse/Saheila moment has been plagued by a lot of issues over time, so that was probably just added at some point trying to solve things, and never removed.