Wow, looks like you've already put a lot of thought into this. All the best with it - I really like the fact that you are aiming for a campaign map and not just a multi-player mod.

I don't know that much about the period, but I recall playing a boardgame of Saratoga by Richard Berg. In his designer notes, he described warfare in the period as largely "decorative". It might be hard to simulate with the brutal TW engine. Maybe lower morale and weapon lethality (rifles excepted)?