If you're after some great European stuff, you should contact teams the 1648, Italian Wars and Call of Warhammer Teams. While not all their stuff might not necessarily be period appropriate, there is some great stuff there and I imagine it would shave quite alot of time off setting up all of the rosters. I mean I guess as you said, you want to make your mod unique (atleast I think you did? haha) so I can understand if you were hesitant on utilizing the work of others, but for efficiency's sake it might be an idea to explore, it'd also allow you to focus on your native american factions allot more as well, limiting the work load and the number of team members you need.
Just a thought is all, best of luck and love the map! Its gorgeous!