Dan: Your information and postulations make a lot of sense to me. One other factor springs out of the pages and that is that Lewis, Davies and Floyd are all Welsh names and there was a mass exodus of Welsh during and after the English Civil War right through to the defeat of Bonnie Prince Charlie at Culloden in 1745. Because they were (nearly) all Roman Catholics trying to survive in British Protestant Colonies they would have flocked together, and maybe taken native wives for lack of catholic possibilities.
I am presently studying back copies of the Transactions of the Cymmrodorion (Welsh) Society as there is much information therin about expatriated Welshmen, including the expedition of John Evans into the Missouri and Mississippi valleys in 1795 searching for a descendants of a lost party of Welshmen who may have discovered and explored America about 1200 A.D.
History was never this exciting when I went to school sixty years ago!