I was pleased to see a post about the 1-4 designation. I'm not sure in anyway that I have information that pertains to you directly, but others may stumble upon this at some point.
However, it does lead you down the rabbit hole of world history.
The Shumate family, when seen along side families that moved from NC/VA to PA and KY, appear to be a variation of the Schumacher/Shumake/Shoemaker/etc families.
The Shumate I am familiar with relates to the Harrison and Standly (Stanley) families. This should be a public link to her photograph and tree.
Sarah Carmichael Schumate: http://trees.ancestry.com/tree/25674505/person/1899611600/me...
An internet search of "Harrison, Evansville, Indiana" should bring up various tidbits about who the Harrisons were.
A similar thing can be done with the name "Stanley" in Virginia news archives. This will often yield stories about the "Stanley Tribe" or "Stanley Clan."
It was tradition in the families I am speaking of (pre-1900/1920) for the father to arrange the first marriage. Because of this, there is a very high rate of 2nd and 3rd marriages. I am familiar with many of the names you listed as cousins and in-laws of step parents.
Robinson, Miller (sometimes seen as Muller), Gray, and Wells.
I am familiar with the Bowers name through the study of comparing folk history to "accepted" world history. I also happen to have a close friend who is a Bowers/Stuart. Many his his gg grandparents generation were listed a quadroons.
The I-4 designation for my family came about quite by accident. My grandmother, a Rose/Gluck-Click, from Eastern Kentucky started showing the somewhat typical signs of aging when she hit her early eighties. She was getting more and more forgetful as time went on but there was no evidence or suggestion of early Alzheimer's. After about a year of tests it was determined by a few doctors in Florida that she had a variation of Lewy Bodies Parkinson's Disease.
One piece of information given by a doctor, during several DNA/blood tests, was that she "...had an ancient and uncommon blood workup..." This seems consistant with the I-4 type.
I am in no way qualified to suggest what the I-4 type means as far as ethnicity or origin is concerned. But I assume if enough families with this designation speak publicly about their direct families---common denominators will appear.
The work I do revolves around the first known families of Eastern Kentucky. I work with a group of names that averages around 20,000 at any given time. Where are they believed to be from? Where did they move? What history accounts for their various moves at these various times? Who did they marry? Etc, etc.
In the families I am speaking of there are a few interesting findings.
1..Many of the German people that went from NC to PA were Hessian soldiers.
2..Many of the Irish were actually from Northern Ireland---making it far more likely that they were actually "Scots."
3..Many of the "Scots" came here under Oliver Cromwells reign---during the Jacobite era. This means our "Scottish" distant grandparents could have really been from any of about 10 countries.
4..The earliest members of all these families often come from Wales or The Netherlands. The Welsh are genetically linked to Spain. And at this time in Dutch history you could have been Spanish, "Norman", "Germanic" etc.
5..There are also many lines that came over with the French Hueganauts...but are clearly not "French."
Again, I don't believe I have the answer and my opinion changes daily. But these are the 5 things I have run into over and over and over.
What kind of people come from somewhere...but aren't actually from there????
History gives us about 10 answers to this question. Maybe the full answer is in the I-4 label.