Thanks to everyone for some great (and some tough!) questions. Feel free to ask more. But I thought I'd get started answering.
First off, May asks: "The motive for murder in Why Mermaids Sing still haunts me. And to find out that it actually happened shook me a little bit. So what I'd like to know is if you plotted that story around this real case or if it just fell into the storyline you already planned?"
May, I read several books on shipwrecks as part of the research I was doing for a book I was writing called Beyond Sunrise (which will soon be available as an ebook with an all new cover, by the way!). At the time, I was only kicking the idea for the Sebastian St. Cyr series around in my head. But that story haunted me, too, and in the end it formed the core idea around which I wove Why Mermaids Sing. I actually had the ideas for the first four Sebastian books and their titles (well, my fourth title was Where Dragons Live, but I wasn't allowed to keep it because it sounds too fantasy-ish) before I started writing What Angels Fear.
May also asked, "Sebastian's love life: was it Hero from the beginning or did it change across time as you wrote it? I think I can answer that question along with this one from Veronica:
Veronica says: "I was wondering if you ever bounce ideas off your family or friends when you're stumped or conflicted about what direction to take with your characters. For example, when I first found this series I loved it and promptly set about perusing many of your old blog posts where you talked about the books and/or your writing. I came across an answer you made to someone in the Comments section where you said that you had toyed with the idea of having a pregnant Hero sail away from England and out of Sebastian's life but that you ultimately decided you couldn't do that to him (and thank the book gods for that!!!!). Do you ever run those ideas across your trusted inner circle to see how they might land? And, if so, who do we have to thank for convincing you to let Hero stay?"
Veronica, I do bounce ideas off my family ALL THE TIME (and they still put up with me! Amazing.). I did it with Samantha when she was still quite young (as in, twelve). I still occasionally do it to her and to my younger daughter, Danielle (who has a tremendous grasp of plot arcs and character development, by the way; in her heart of hearts I think she wants to be a writer). But when Steve and I married, he became my main plotting partner. I always hash my stories out with him at the plotting stage; it's so much easier to think things through if I can brainstorm with someone else. And I'll frequently go to him and say, "I have a problem; can we talk this through for a bit?" And he always says, "Sure!" quite happily because he knows my problem is with my manuscript and not with him.
So that answers the first half of the question. As to my plans for Sebastian's love life, from the time I started writing What Angels Fear, I knew where I wanted that part of the story to go. I knew Kat was Hendon's natural daughter and that the truth was going to come out and blow up Sebastian's affair with her. I also knew I wanted Sebastian to end up married to Hero. This was reinforced for me when Hero really leapt off the page the first time I wrote about her. However, I'll admit that when the time came, I had a hard time making that pivot in What Remains of Heaven. Part of it, I suspect, was pushback on social media from readers who desperately wanted the HEA (Happily Ever After) for Kat and Sebastian. The problem was, even though I could understand the yearning, I knew it would be unrealistic (apart from which I knew Sebastian's marriage to Hero was needed for the strength of the series arc). Kat hadn't spent the last seven years saying no to Sebastian for his own sake only to suddenly turn around and say, "Oh, okay; I'll marry you and ruin you." And while it is true that some men did marry actresses and courtesans in the Regency period, they suffered terrible repercussions in terms of social ostracism (as did their children). I did not want to deal with that. Added to which, Kat couldn't have continued on the stage as Sebastian's wife, so what would she have done with her time? She would have been ostracized by society. And unlike Hero, Kat has no interest in social crusades or solving mysteries; she is very serious about her career. But ironically, it was actually Hero who gave me the hardest time; as much as she was (reluctantly) attracted to Sebastian, she really didn't want to marry. She wanted to sail off on adventures, and I had a hard time talking her out of it. I hashed that aspect of the series through with my family a lot. I mean, A LOT. We're talking months of agony. All are very good (and experienced); they don't try to influence me. They simply let me talk and talk until I convince myself of what I need to do. I also talked about it with my Monday night writers' group, the Wordsmiths. (We've been meeting since I first moved to New Orleans; it was through the group that Steve and I got to know each other.)
Also, you might be interested to know that my original ending for Heaven was much more ambiguous. My editor made me add the final scene at dinner where Hero says she'll stay for her mother's sake. My editor said, "You can't make your readers wait a whole year to find out if she stays!"
I'll be answering more questions in future posts, so stay tuned!