Ellen Shindelman Kowitt
Because you mention that David Levy served in a German battalion unit at Valley Forge, and his wife was born in a German-speaking area, it raises the question about whether he might have been of Ashkenazi origin.
All early American Jews were not all Sephardic. It is true that synagogues operating at the time in America were practicing Sephardi rites, but there are highly visible examples of those who were Ashkenazi that actively participated and intermarried into those communities. One notable example is the religious leader of Shearith Israel in Manhattan in the late 1700s, Hazan Gershom Mendes Seixas himself, was the son of a Sephardic father and a mother of Ashkenazi descent.
DNA: Not always passed down through all lines, so just because your DNA results didn't show any Jewish, doesn't mean it's not possible. This is assuming you took an autosomal DNA test.
David Levy is listed in the Daughters of the American Revolution ancestor database (index) as #A069673.The dates differ with him born circa 1740 and death as before 1-18-1804. He was a non-commissioned officer shown as QUATERMASTER SERGEANT, ALSO PVT IN CAPTS KEEPORT, BALTZEL, BUCHARDT, BUNNER and LCOLS GEORGE STRICKER, LUDWIG WELTNER; GERMAN REGT, CL. His wife's name is slightly different as well and listed as Barbara Weisser.
Ordering Genealogical Documentation from DAR:
More information can be purchased about any patriot ancestor appearing in the DAR database for $10-$30 to see supporting documentation and/or descendant applications including significant genealogical detail about relationships. To search, visit https://services.dar.org/public/dar_research/search/default.cfm?Tab_ID=1. Once you find someone in the results, click on the "PURCHASE" button to order. If more than one descendant application is available, select the one most recently submitted which will be the last one on the list.
Intermarriage in 18th C. America:
The prominent colonial Jewish gentleman, Simon Gratz of Philadelphia, may or may not have married a non-Jewish woman whom he sired 7 children with. All of the children were raised Christian, and there is no evidence their parents, Simon and Mary Smith married. There are other examples in this time period of similar relationships between Jews who remained involved in the Jewish community but "married" or coupled outside of the faith. Your description of baptisms and roles in the church for David Levy's family are consistent with this. Were they always affiliated with the Lutheran church or another? Some churches excommunicated members for marrying outside of their faith. And where are David Levy and his family buried?
A new JewishGen US Research Division website covering 1624-present will provide links and guidance on research for all periods in America including colonial Jewish families. Suggestions or materials for content are welcome.
Ellen Shindelman Kowitt
Director, JewishGen US Research Division