Very well done! A couple of questions WRT the setting more than anything else:By 1783, America was lost, but the Brits held the south and the USA was grudgingly forced to accept along with Canada, Britain would hold South Carolina, and Georgia, alongside Florida. The Brits named the remaining southern colonies, the Colonies of Fidus, or simply, the Loyal Colonies. In 1812, it was invaded by America under General Andrew Jackson. General John Moore, exiled to Fidusia after his failure against the French resulting in the 1809 Battle of Coruna - which saw British troops successfully evacuate Spain temporarily before coming back with a rage under Wellington. Moore defeated the American invasion, becoming the 'Isaac Brock of the South' and successfully stabilized the frontier with America by 1816. In 1890, the colonies were federated like Canada up north and in 1891, Fidusia became a semi-independent dominion of the British Empire before becoming fully independent in 1931 during the Statute of Westminster. Today it is a country of 40.8 Million with a GDP Per Capita of ~$56,000, being a very economically prosperous nation and it uses the Fidusian Pound (pegged to the GBP) as its currency.
1) You mention Canada still existing up north, does being sandwiched between two British realms impact U.S. growth or safety? Since events like the Statute of Westminster still occur despite the POD, I'd imagine Anglo-American relations could be fairly close to OTL, but then again that much territory under Britain could be a threat too.
3) I get that British rule means abolition probably progresses full steam ahead, but how are race relations overall in Fidusia? Are demographics any different from the region in OTL?
4) Surprised that South Carolina didn't get renamed to something like "British Carolina" or "Clarendon", was that an oversight, a deliberate choice in-universe, or a case of in-universe laziness/bureaucratic inertia?
Also, kudos for not putting the border at 36'30; other than in Glen's DSA timeline, that cartographic choice IMO is just an eyesore.