When someone says "Republic", I can't help but think of Rome, and the TV show of the same name. I'd think that Anglea was a much warmer place, but environmental events turned it into the permafrosted island that we know it happened maybe two to three hundred years ago. Long enough for them to have adapted and know no other way of life. This would explain why they're a power player in an industrial steampunk world when they're located in a permanently frozen wasteland; good infrastructure.
So they're kind of a Roman/Eskimo fusion culture, surviving off game and fish mostly, as well as a few hearty plant types and quite possibly mushroomsand other low temperature/low light agriculture. I chose the Eskimo culture based off the look of the Anglean engineer outfit, how it seems to fit them a bit more than what I think what vikings wore, but whos to say it isnt a roman/Eskimo/Viking hybrid, which would rock.
The Romans also kept slaves, and what I have gleamed from the Rome TV show and my latin language books, being a slave wasn't torture (As opposed to waterboading, the rack, iron maden, etc...), more like a crappy to okay job, depending on who your master was.
Touching on the hospitality aspect, northern Canada is dotted with Inuksuks (Took me a sec to type that one out :p) wich serve as roadsigns and even food caches, I'd hope to see them in Anglea if the Eskimo aspect is taken up.
Being extremely innovative, I'd think that a different kind of profession would arise, the Fixers. Fixers are a mishmash of engineers and doctors; they have a knack for knowing how things work, whats wrong, and how to fix it quickly and with materials available. Veritable Angus MacGuyver meets Gregory House. Fixers are looked down on in the capital, where there are actual doctors (world class kind) and engineers (Also world class), but are keystones to the fringe settlements; no raiding party would dare leave port without their Fixer.
Despite these prejudices, Fixers and Engineers would travel between the interior and the fringe frequently, to expose them to the variety needs people in different areas have, and to build new inventions for the job. Hearty, multifunctional inventions. Fixers and Engineers would come up with an idea, and present it to a body of their peers in the interior, like Kinforth. They would then be given a grant and residency in the interior to prototype and produce their invention. Depending on the magnitude of change their invention brings, and their personality, they would either head back out to come up with a new invention, go back to living their lives, or just live gluttonously off their invention, maybe even start a small dynasty.
I also see that the Republic Allthing (Where the hell did you get this idea :s), like the Roman governing body, appears to elect any Anglean citizen, but is heavily influenced by nepotism. If your family is rich and a relative is in the Allthing, you've got a very good chance at being an Allcaller (People that make up the Allthing, maybe its called the Allsong?).
Id think that the people themselves seem simplistic, but are rather very pragmatic, and not stupid. Simple in a Captain Carrot sort of way. Why have thousands of people on both sides of the battle die, and maybe loose, when we can simply kill a handful of commanders, win, and most people live (to be thralls!)?
Hows that for input.