Thank you! A lot of good observations there.Congratulations! A very interesting timeline and enjoyable to read. Very deserving of a book.
Setraland seems to have lost a lot of its initial advantages, but I suspect the cultural relations with Europe will allow it to replace quality with quantity. Securing Ohio, even if it is passed the Niagara Falls, gives them a good base for future economic development and river routes to spread their influence throughout the continent. Assuming the complicated nature of the realm doesn't bring it apart.
I think the Viking longship design was important for making Dun Cormac/Montreal viable versus Fhearga/Quebec City, but when the age of sail arrives I think Fhearga will end up as the greater port and economic centre like Quebec originally. Quebec came from the Algonquin word for “narrow passage” which made it hard for large sailing ships to push up the river. The Age of Steam, plus an easier southern connection, allowed Montreal to overtake Quebec City.
The Longship might ironically give Setraland an advantage on the great lakes, having the superior naval force. Eventually though that might be lost as the first nations can be quite adaptive. I do wonder if 'Hudson Bay' has been found yet, either by wanderers or monks seeking solitude, but I guess the ice will keep them away for now.
Random question for Africa, but since Ismaili is not as missionary Islam and 'Carthage' is christian, what happened there? I suppose if there is a Mansa Musa equivalent they can't go on the Hajji. Maybe if you want to throw in more cultures a ruler gets the sweet tooth for the sweets from across the sea and sends an expedition west. That might be more silly though.
There was a Christian equivilant to Mansa Musa. The Guide will go more in depth, but the Gaelicians had a lot of fun going along the Western Coast of Africa.