Before we start, I wanted to say something about continuity and canon. I don't represent Wizards of the Coast, obviously. This was a very fun project, and I had a lot of freedom in developing Davriel, Tacenda, and the lore of the Approaches. However, I can't state or make official Magic canon, beyond the extent of what is in the text of the story.
So, when I answer these questions, I'll often have a couple of different terms. If I mention Official Canon, this is (by my understanding) the current canon of the Magic storyline--as explained to me by the local in-house experts. I could be wrong on this sort of thing, but I'll try to pass along my understanding of what the canon answer is in relationship to this story. (For example, I was assured it was okay to have female demons in my story, despite it not being something that Wizards has done very much in the past.)
I'll relate my own Head Canon on other items--things that I haven't cleared with Wizards. This should be taken as what I was going for, and can work for your understanding of the story, but it shouldn't be taken as gospel--and it could very well be contradicted by future decisions by the lore team. They take their continuity very seriously, and I am not up-to-date on everything they're doing with the stories of the other characters. I was pretty focused on my little corner of the multiverse.
In other places, I'll talk about decisions I made (or didn't make) in relation to the story--if I am talking about the process, you shouldn't infer too much from decisions I didn't make. I did a lot of this work before talking to the lore team about larger continuity, so things I considered (and discarded) before the story was finished shouldn't be taken as hints for the larger story. To be honest, I didn't know much about it at that stage anyway.