This appears to be a complete myth. Wendell Mueller/Miller, his parents, siblings, spouse, and children are all well-documented. Wendell was born in Germany about 1733, came to Pennsylvania with his parents and lived in a Pennsylvania German community in Pennsylvania. In 1752 Wendell moved to North Carolina with his parents and a number of other German families. Wendell's father, Michael got a land warrant in 1753. Wendell married a member of that same German community in 1755. Wendell and two of his sons, Frederick and Philip, fought in the Revolutionary War.
Wendell Mueller was a single young man when he arrived in North Carolina. He certainly did not have an Indian wife when he lived in Lancaster, PA. Wendell wrote a very clear will naming his wife and all his children (and some of their spouses) in 1804. Son Frederick was born in Rowan County, NC in 1756 as stated on his Revolutionary War pension application. He made no mention of his parent's names. The Indian story seems to be based on a statement of Frederick's son (Wendell's grandson), Michael, made in 1853 when he was about 70. He says only that he had been told that his parents, Frederick and Margaret Braun Miller, had a son named John several years before he, Michael was born and that the child died as an infant of smallpox, acquired from his grandmother who also died and was buried with the baby. There is no mention of any name for the grandmother, or any suggestion that she was a Native American. She is likely to have been Rosanna Brown, Margaret's stepmother, since Wendell's wife Christina Fisher Miller was alive and well in 1804. It's also possible that Michael was simply mistaken about the family story since his parents were married in May of 1779 and he had at least one older sibling, a sister Margaret born about 1781.
