Maybe have the eventual state of 'Louisiana' include only the southern (more francophone) portions of its OTL counterpart, and combine the northern area with at least part of OTL Arkansas? And perhaps have the River Arkansas, rather than a line of latitude, as the boundary between your equivalents of Kansas and Oklahoma? I'm doing both of those in my own TL, "Wider Still, And Wider", in which 'America' was a dominion within the British Empire at the time of that expansion...
Also, how about merging the LP portion of OTL Minnesota into TTL's equivalent of 'Iowa'?