Sorry it's taken me so long to comment, I read the story this morning at work but wanted time to read it again before I commented.
First of all, I *do* know how you feel, I posted my first fanfic a few days ago, and it is hard leaving your baby out there all alone at the mercy of strangers.
I'll start with some things I liked about your story. I'm not a big fan of slash, but I thought the overall storyline worked pretty well. Although there was one aspect of her personality that I had questions about, (more below) your PC, Fuscienne, worked well in the context of the story you were telling. I did like the fact that you included Anomen as her friend and confidante even though they weren't romantically involved. More often, unless the PC is romancing Anomen, he's characterized as the party's resident arrogant jerk.
Okay, things I thought needed improvement.
First, it was unclear to me what exactly Fuscienne was so depressed and worried about. Was it guilt over having turned into the slayer? Worry that it might happen again against her will? I couldn't tell. When you start talking about "it" being the reason Jaheira and Imoen left, my first reaction was, "Well, what the heck IS 'it'?"
There were also several places where I felt the dialog or actions sort of "came out of the blue" without enough foreshadowing or any real connection to what had happened before. For instance, I would have preferred to have seen some hint that she was interested in Sola before he showed up to comfort her. Also, later in the story, the para that starts "It made her feel a little strange to be called 'my lady'" seems to have little connection to what comes before or after it. Maybe you felt there were things in that para that needed to be said, but IMO it sounded quite forced. Then, a few paragraphs later, she has a conversation with Sola where she thanks him for comforting her. His response is a question about whether she is involved with Anomen. Maybe I'm old fashioned, but IMO saying 'thank you' when someone is kind to you is generally not considered the equivalent of "I want you, baby", so I was baffled by Sola's response.
Now to what I consider the single biggest problem with the story...your reliance on PLOT DEVICE VILLAINS to move the story forward. I counted what, 3 or 4 places where a bad guy just appeared out of nowhere (sometimes literally) to put the good guys in peril so you could have the PC show her love for Sola, or Anomen show how conflicted he was about Garrick etc. There's nothing inherently wrong with using conflict with 'red shirts' to help drive the interaction between characters, but it has to be a natural outgrowth of the story you are telling. The only one of the battles in your story that kinda worked in terms of providing a natural progression of the story was the Trademeet crypt one. The last one, where the woman suddenly threatened Keldorn's daughter with a knife, was IMO not just contrived but painfully contrived.
One more comment. I know absolutely nothing about how homosexuality is regarded in Faerun, but since your treatment of homosexuality in the story seems pretty much identical to real life, I'm going to comment on Anomen and Garrick's relationship in that context. It seemed that you were suggesting that neither Anomen nor Garrick had had any gay relationships or even interest in other men "that way" until the incident in the cave. Now *that* severely strains my suspension of disbelief. For one thing, my gay friends are pretty much unanimous that it doesn't work that way.
I think it would have been much more believable if at least one of them had either had a gay relationship or at least acknowledged feelings of that sort before the story takes place. Garrick would be the obvious choice, since he is quite accepting of his feelings for Anomen, and (if I can engage in some flagrant stereotyping) he's a *bard* for heaven's sake! Anomen has always struck me as pretty hetero, but for the purposes of the story I think he could be reasonably portrayed as having thoroughly repressed any sexual interest in men. BTW, this would be absolutely trivial to fix. In the discussion between A & G about the girl Garrick had been engaged to, he could simply say that he was secretly relieved it was called off because he found he was more attracted to men.
I hope you find my comments useful. I do think there's the core of a good story here, but I do think you need to do something about those random, plot-device villains!