I just concluded a reasonably long project: writing a murder mystery novella “The Missing Motive” and posting it chapter by chapter online as I wrote. A number of thoughts on this project have been bouncing around in my head and I wanted to write about them at greater length. There will, naturally, be SPOILERS.

1) Did it do what it was supposed to do?

Or, in other words, did writing this novella and posting it chapter by chapter with minimal editing help reboot my writing drive?
Yes, yes it did.
That's why I'm writing this, in fact. I got so worked up writing that story that I didn't want to leave it when I finished. I wanted to share more about the story and the characters.
It helped this project that I was working with characters that I had already written about before. In some sense it felt like I was returning home to familiar ground. These characters already worked and I knew from their first outing (Tyndale, Melody, and Kalyana all appeared in “The Delicate Game” in Heat 10) that I could already do a mystery-like story. I was building everything on solid ground.
At the same time, I was exploring them all anew. I understood these characters, but I learned more about them as I wrote, Melody especially. I knew the genre, but I was learning a ton by writing deeply in it for the first time. That sense of giddy discovery also helped propel me to continue writing.

2) Defying genre expectations

I love a good, classic British murder mystery. Give me a posh accent, a glass of port after dinner, and a dagger in the back any day of the week.
But there are a number of conventions of the classic murder mystery that I wanted to subvert or do away with entirely. I'm not a big fan of the dim-witted assistant (Watson or Hastings) or the cocksure policeman (Lestrade or Japp), who exist largely to point out how skilled the detective is in comparison. So I made my assistant—Melody, in this case—be an intelligent character in her own right, but someone whose intelligence extended in other ways than the analytical ability of Tyndale. The inspector, here never mentioned as anything other than a “wolf sergeant,” was skilled at his job, but woefully understaffed, necessitating Tyndale's involvement.
Another subversion that was fun was allowing Tyndale to be the heroic detective, but turning him into a reluctant one. He doesn't want to take on the case. It's not because he doesn't have a personal stake in the matter (he was good friends with the deceased) and it's not because he doesn't find the case interesting. Instead, he realizes that this is a life and death matter and that, having lived the fairly coddled life of a Baron, he is not prepared for the consequences that would bring.
One trope I tried to subvert and failed was having everyone be suspicious. “The Missing Motive” was styled more after Christie's mysteries than Doyle's. There is a very clear list of possible suspects. But Christie often superimposes a number of other bits of skullduggery on top of the murder to make characters act suspiciously or toss in red herrings. I often find the sheer coincidence of all these events happening so close together to be jarring, and I had resolved to do nothing of the sort. Then I got a few pages into writing “The Missing Motive” and realized I could not have everyone acting innocent because then there would be no tension. So I tried to focus the outside events to a single one (Mrs. Ashbury's affair) that would have rippling effects in several other character's actions, including Mr. Ashbury and Dahlia. I did my best to restrain coincidence to a single occurrence: Stuart not being at the pub.

3) Making an anthropomorphic murder mystery

The discussions of a furry mystery on the Furry Writers Guild and some of Rechan's questions there were a big impetus for creating “The Missing Motive.” From those initial ideas, I was reminded that I had tried to do a mystery in miniature with “The Delicate Game,” and played around with the idea of Tyndale becoming a true detective. Then I hit upon the idea of him trying to solve a murder where no one had any reason to commit the crime.
It was not until I sat down and started writing that I had to start asking (and answering) questions about how a murder mystery would work in a furry world. “The Missing Motive” doesn't make use of its furriness in too many ways, but scents, in particular, played a big role.
Early on in the story, I use scents to pinpoint the initial list of suspects. The murder took place in a small room, and small rooms tend to preserve scents, so Tyndale knew that one of those scents had to belong to the murderer. This was also important later in the story when Tyndale meets Stuart and is able to recognize him by scent alone.
This also forced me into some corners as I wrote. I realized, for instance, that I could not simply have the fingerprints wiped off a gun: the scent would need to be removed somehow as well.
Something I'd like to do should I go back, is reference the fact that Tyndale and the wolf sergeant have a significantly better sense of smell than the other characters. That would help explain why the sergeant was able to find the gun, due to the faint residue of gunpowder, and also why Tyndale needed to be away from the home when the gun was fired, due to the murderer not wanting Tyndale to be able to track down the gun too quickly.
The idea of a furry murder mystery that turns on its furriness is a fun one and a big one. I haven't even scratched the surface here. I barely even nicked it.

4) Addressing inequality

I am still unhappy with how I address inequality in historical pieces like this one. In “The Missing Motive,” three types of inequality are addressed: Mrs. Ashbury mentions the struggles of African-Americans, Dahlia mentions the difficulties of being a woman scientist, and Tyndale himself mentions the double-standards held toward LGBT people, and his own attitudes towards such double-standards greatly inform the way the story ends.
I feel like there are so many ways in which addressing these issues can become problematic in themselves. Not addressing them enough can (sometimes literally) whitewash history; however, addressing them too much can treat minority characters as if they are nothing more than their minority status. I'm not satisfied with how I did things in “The Missing Motive.” It's something I want to continue working on.

5) Readership

I followed how popular the chapters were as I was posting them. Oddly, I noticed every chapter would spike after I linked it on Twitter, despite Twitter itself telling me that only one or two people followed the link. Also, as one might expect, retweets and the like also spiked viewership.

6) Changing the story as I went

The actual formulation of the story was an odd one. I was already writing—and writing a murder mystery no less—before I had a clear idea of what all the events of the story would be. The last thing to fall into place was Basil's gun, which I didn't conceive of until the time I was writing chapter 4 or so. I was pleasantly surprised by how little preparation I needed. Mysteries have a nice rhythm where important events happen (or are discovered) and then must be discussed, understood, or followed through to their conclusion. The initial murder itself carried me through several chapters of needing to interview all the major suspects and isolate where they were and what they were doing.
Some throw-away lines early in the story became important later on. When I first wrote about Dahlia's diaries, I had no idea I would reference them twice more, once when she burns one and later when Tyndale confronts her about the identity of the murderer.
I think the ending had the most interesting development. I knew who committed the murder and why before I sat down to write, but I was having trouble figuring out how that would be revealed. I originally envisioned an Agatha Christie ending: Tyndale would confront everyone in the sitting room, reveal secrets, expand on his theories, and finally point out the murderer, handing them over to the authorities in the process. In the next iteration of the ending, the murderer tries unsuccessfully to kill Tyndale and then commits suicide.
But I wasn't satisfied with either of these endings. I kept thinking that Tyndale would want to do more, that he would want to save the life of the murderer if he possibly could. This led to the ending in its current form, but also to an insight into Tyndale's character: he isn't obsessed with justice or with criminal psychology like some detectives; he values life and the freedom to live as one chooses.