North Carolina was the known location for the Brown County Sides, Peacocks, Briggs, Hedricks, etc and they most likely were not asked. The same thing happened with Elizabeth Peacock Hedrick in Adams County. The census taker in Missouri did not know the newly arrived Michael Sides and had to ask. There is also the case of the elderly living with children and grandchildren who answered for them.
Delila was the aunt of Elizabeth Briggs Stephens through and in-law relationship. Delila was also her first cousin once removed.
When James and Daniel Stephens under took the Mormon Baptism of the Sides they used the in-law relationship.