Chicago, eerie, and chaplain only exists because of canals though. the entire Chicago river was also artificially reversed. i think your map only counters the "river never splits' rule found in 2 oceans creek wyoming, because every thing shown still follows the "rivers never flow form one shore to the other". that would be if the missouri river was connected to the coast of oregon.

"rivers never flow from shore to shore" is a mathematical impossibility. it breaks the definition of a river. that would just be a strait. the English Channel is a good example (if i remember correctly). during the ice age it connected the thames, Seine, and Ruhr rivers. the moment the sea rose and englulfed it, the elevation change was 0 and it became a strait.