It's very intriguing, and your writing is beautiful. I hope it was useful to get these chapters, and the letter and painting, out your virtual door to me. I think you're moving in an excellent direction, and I don't want to say too much more, because I want you to be drafting, not thinking about what you've already written. So please don't mistake my brevity for lack of interest, quite the contrary.
I'm interested in what you said about numerous villains, and would like to caution you only about one thing: getting Mina into an Alice-in-Wonderland situation where she pits herself against a succession of characters. She's a very strong character, and the setting you've established in the first 3 chapters is very emotionally involving. Her personal growth, and her relationship to the characters that are already present, and to those you are going to introduce, seems to me like the heart of the story as it is so far.
I'm looking forward to seeing what comes next. Once again, I'm sorry about your friend. You write about her so beautifully, with a strong sense of story even in this situation. Although it may be hard for you at times to write about the death of your mother -- the death of any mother in your books will be about your mother -- it will provide a strong backbone to Mina's experience. One of my rules of thumb is that if you're shaking as you're writing, you're on the right track.