I don't believe this Michael Yohe was descended from the Michael Yohe b 1746 in Germany who immigrated in 1754, married Anna Maria (Mary) Shouse, served in the Revolutionary War, moved to Washington County PA around 1794, and died there in 1832. I've done a fair amount of research on this Michael's family (he is my g3gf)
Michael's sons Jacob and Isaac each had a son named Michael. Jacob's son was b 15 Jun 1809; Isaac's was b 2 Oct 1815 -- both in Washington Co. PA. These are the only two Michael Yohes that appear in the baptismal records of the Mt. Zion church; there is no Stephen Yohe listed there.
I don't have much information on Jacob's son Michael, but his birthdate doesn't match your Michael b 1815.
Isaac's son Michael married Phoebe McConnell and lived in Washington Co. PA all their lives, I believe.
I found a couple of trees in Ancestry.com -- http://trees.ancestry.com/tree/12714541/person/-197994751?ss...
= for one -- giving a Michael b 1813 with children whose names roughly match the names you mentioned, and ancestry Michael -> George (1777-1851)-> Michael (1748-1785) -> ?. Not all children's names match, and other facts don't match your narrative, so I'm not sure what is correct.
Another tree -- http://trees.ancestry.com/tree/16533634/person/498770247
-- traces this line back to Adam Yohe b 1722 in Germany. I believe Adam immigrated to the Easton PA area in 1749 and may have been a cousin of Georg Conrad Joh, the father of Michael (1746-1832).
I am in the process of starting a Yohe Surname Y-DNA project on worldfamilies.org. Y-DNA is passed from father to son with rare minor mutations, and is a reasonably reliable way of determining whether two males might have a common male ancestor. If you're interested in participating, please contact me.