strange coordinates and lines

Beast Business, Ilona Andrews

The Amazon description says this a novella, but it's actually a shortish novella, a related short story, a short vignette, together with several short stories that were previously on their website. Everything's from their Hidden Legacy world, and if it fits into the existing pattern will be the primer for a trilogy focusing on the third Baylor daughter, Arabella, finding a partner. OTOH, Arabella really only makes a guest appearance in the novella and it instead revolves around a couple of secondary characters from the preceding two trilogies.

Diana Harrison, Prime of House Harrison, needs illusionist prime Augustus Montgomery, Prime of House Montgomery, and owner of massive PI company MII, for an urgent recovery operation. House Harrison's thing is animal magic, and someone has stolen a unique tiger cub from them. They have 24 hours to recover it because it needs its mother's milk, which means Diana needs Augustus personally, and she's coming along whether he likes it or not. But they both have their secrets, including the true nature of their magics, and they're going to have to cooperate closer than Augustus prefers. Shenanigans ensue.

The Masquerades of Spring, Ben Aaronovitch

It's the Roaring Twenties and Augustus Berrycloth-Young is enjoying the high life in New York, ably aided by his American valet Beauregard, and his friend Lucy, who can be trusted to know where all the best Jazz in Harlem can be found. Into Gussie's pleasant idyll comes a reminder that he is a keeper of the sacred flame of the Society of the Wise, in the form of the Folly's top magical troubleshooter, Thomas Nightingale. Nightingale is on a mission, pursuing the origin of an enchanted, possibly cursed, trumpet, and he's absolutely sure Gussie is the man to help him track it down.

I'd say this was meant to be a Jeeves and Wooster homage, Nightingale even introduces Gussie as 'Bertram Wilberforce' at one point, but Beauregard really doesn't get much to do. Instead it's Nightingale, Gussie, Lucy and the mysterious Cocoa against an escalating array of music agents, bent cops, and political operators, all complicated by Gussie trying not to let Nightingale know that he and Lucy - Lucien Biggs - are a couple. But never let it be said that a Berrycloth-Young failed to rise to the occasion!

IOW it's a very atypical Rivers of London novella, but Gussie makes for a thoroughly entertaining narrator.

The Vampire and the Case of the Wayward Werewolf
The Vampire and the Case of the Secretive Siren 
The Vampire and the Case of the Baleful Banshee, Heather G Harris and Jilleen Dolbeare

Think Due South meets Northern Exposure, with the out-of-place protagonist role played by a London partygirl, rather than a Mountie or a doctor.

A fortnight ago Elizabeth Barrington - Bunny to her friends - was a partygirl about town, then she woke up dead and decided a century of servitude to the king of the vampires just wasn't going to happen. Now she's the newest recruit to the police force of the small Alaskan magical town of Portlock, bringing the total strength of the force up to three - Bunny, Gunnar the Nomo (chief of police), and Sidnee, a friendly siren. Bunny was theoretically hired as an admin assistant, but Sidnee mostly mans the office, and one man, even a man-mountain and alleged demi-god like Gunnar, can't manage 24 hour coverage on his own, so pretty soon Bunny, and Fluffy the rather too intelligent Alsatian, are neck deep in a complicated murder case, variously aided and hindered by the town's political movers and shakers, including smooth vampire Connor Mackenzie, rough-and-ready polar bear shifter Stan Ahmaogak, and human hunter Thomas Patkotak.

Book 2 has Bunny being formally sworn in as Officer Bunny, but she's barely had time to get used to that when an encounter with a new drug almost takes out Gunnar, turning Officer Bunny into acting-Nomo Bunny, and leaving her with a drug crisis to take care of, with the competing help of Connor and Stan. Gunnar's back for book 3, but Sidnee's definitely out of sorts, there's an arsonist about town, and there's an escalating series of thefts which threatens to bring down Portlock's protective shield, and there's definitely something dangerous out there in the wilds, waiting for its chance to feed. 

3 down, 9 to go.