Ohio should probably be counted in the independent zone. It was flooded pretty quickly after the revolution, and Britain didn't really contest it. there were few natives, and it was wide open. Likewise, lower Illinois/Indiana were also in the independent zone. The real contested (OTL US and Britain) part was upper Illinois/Indiana, Michigan, Wisconsin.
Virginia had the best claim on it, with NY, CT, MA making claims, too. Pennsylvania, oddly, did not make a claim per the very limited research I did, although here the US could claim it through CT. settlement of Ohio was primarily from NY and New England in OTL, although in TTL ability to travel across several countries, all in a state of agitation while settling claims/differences) might here affect migration patterns. (hmm, this brings up a consideration. OTL the crowded masses migrated from NY/New England. IF the ability to move about restricts that, the region is going to urbanize quicker than in OTL).
OTL, the states miraculously settled differences peaceably (part of the real life wank that was the US), but now that they're all separate countries, it's hard to see them not coming to blows.
but, in spite of all my nitpicking, I do like the TL.