So I started making a list of british actors for varied parts. A lot of it is variable, as most of Temeraire is a bunch of Uptight British Gentlemen types, and England makes those in Bulk.
HOWEVER, as I was doing it, the cast list looked very...white. In future books/seasons where they go to other countries, this list is expanded, of course, but still. I thought 'well it is a historical piece, so it is accurate' and then I threw up on myself and came to my senses. It's all made up anyway, and Naomi Novik herself came up with a plausible reason to have women lead characters. I could do the same!
I still do want Will Laurence to be played by a white man, specifically this one:
Charlie Hunnam, of Pacific Rim and King Arthur fame. The Perfect Twunk British guy who's all strong looking, but could play both the Very Proper (Awkward) British Gentleman, as well as a fun loving dragon dad, and a feral warrior captain. He's our fish out of water character, so it makes sense he's as close to our idea of old timey british man as we can get.
NOW THOUGH: The aviators in this series are canonically lower staffed as it's hard to find people unafraid of dragons, plus they're a bit looser with the rules: as long as they get people on the dragons, they dont much care who they are, and dragons certainly don't give a damn about racism. Therefore, I think *historically* it would make sense as a career for a Freedman, or a Freedman's son, who may not have many prospects.
THATS RIGHT ITS A PACIFIC RIM REUNION
Canonically, John Granby is lower-class, and was sent to the Aviators at age 7 because his family couldn't feed him. This contributes to how bitter he is about Laurence, a gentlemen, just GETTING an uber rare dragon egg with no work, basically. Changing his race doesn't really change his backstory, and in fact enhances the tension with Laurence: We imagine he has had to have worked 4 times as hard as everyone around him to get half as much. Plus, John Boyega can do the physical comedy amazingly once he gets his own dragon (spoilers) who is a fireball.
Harcourt and Berkley can go a number of ways, though I favor Rose Leslie for Harcourt because pretty and feisty red head. Though Bonnie Wright may also work. I have Timothy Spell for Berkley, but again, I just need an overweight british man, I think I can find one.
ITS CERSEI'S TURN FOR A DRAGON, BITCH!
But honestly it's her role in Imagine Me and You (great lesbian film if you're looking) that sets her as the crass but firm leader that Jane Roland needs. Plus, look at her, she could definitely Dom Laurence.
(though if we're opening this up to American Actors, she may have to fight for the role with Charlize Theron....)
For the dragons voice acting, I would like a Chinese-British voice for Temeraire, seeing as he's a Chinese Dragon raised British. You could bring forward some great british voice actors like John Rhys Davies and even, I'll say it, Benedict Cumberbatch. Say what you want, he has a good voice. Also Tom Holland for Levitas. Saying a brittle "You Came!" to his Captain as he dies, in the same tone as Spider-man's "I don't feel so good..." Ugh, I'm gutted thinking about it.
I want to throw Riz Ahmed in there somewhere. Maybe for Keynes, the Dragon Doctor? I can't pin it down, but he feels right for this series. I'd like a few British Indian's among the cast, considering the time period.
for season 2 I think Chow Yun-fat for Prince Yonxiang, Benedict Wong for sympathetic Sun Kai, and Gemma Chan as voice of Lien, the "evil" dragon. In Season 3, we need someone mixed Chinese and Caucasian for Tharkay, and I think Andy Serkis to do voice for the Feral Dragon Leader Arkady. Oh! And change Gong Su the chef to a woman. If you really want historical accuracy, maybe she came with her husband who died (there was another chef who disappeared on the journey). we just need more women of color in here. Maybe one on Temeraire's crew? Hm.
So yeah. I mean, it's not like a lot of them are set in stone, but I'm happy with a few of these choices to the point I can see it clearly in my mind.