1. I believe Harry Gregg is probably Henry Gregg. Elizabeth had only three children, according to the 1910 US Census. [104]

2. From the 1900 US Census, Iowa, Scott, Davenport Township, Davenport City, Ward 6, ED 136, Sheet 4A and 4B, Enumerated 4 June 1900:

Sheet 4A, Lines 48-50:
Robert Gregg; Head; Born June 1848; Age 56; Married 25 years; POB England; Father POB England; Mother POB England; Immigrated 1895; Been in USA 5 years; Naturalized; Occupation - Tailor; Rents Home.
Elizabeth Gregg; Wife; Born Aug 1854; Age 45; Married 25 years; Mother of 3 children, 3 still living; POB England; Father POB England; Mother POB England; Immigrated 1895; Been in USA 5 years.
Robert G. Gregg; Son; Born Apr 1880; Age 20; Single; POB England; Father POB England; Mother POB England; Immigrated 1895; Been in USA 5 years; Naturalized; Occupation - Printer.

Sheet 4B, Lines 51- 54:
Henry Gregg; Son; Born Apr 1884; Age 16; Single; POB England; Father POB England; Mother POB England; Immigrated 1895; Been in USA 5 years; occupation - Printer.
Thomas Wakenshaw; Father-in-law; Born Nov 1821; Age 78; Widower; POB England; Father POB England; Mother POB England; Immigrated 1895; Been in USA 5 years; Naturalized; Occupation - Miner.
Adam Wakenshaw; Brother-in-law; Born Feb 1871; Age 29; Single; POB England; Father POB England; Mother POB England; Immigrated 1895; Been in USA 5 years; Naturalized; Occupation - [hard to read, but looks like] Arthwindow Maker.
Charlie Oswald; Boarder; Born May 1871; Age 29; Single; POB England; Father POB England; Mother POB England; Immigrated 1890; Been in USA 10 years; Naturalized; Occupation - Book Keeper.