Thanks for your message.
You are correct in saying George Rushton's first child with Gertrude is Emily Grace.
However you have overlooked the fact that George was married before to Rose Anna Chell. This is shown in the 1901 census and I have a copy of their marriage certificate, which took place on 24 Dec 1900 at Normacote, Staffs which I believe is a Catholic Church
George and Gertrude did not marry until 1925 4 years after their 6th child was born. Their late marriage could be due to Rose Anna being a Catholic and George had to wait until she died before he could marry Gertrude. Their marriage certificate describes George as a widower and Gertrude as a widow. But George's first marriage gives his father's name as George and his second as Thomas. Like you say.
The name Thomas could be wrong. My own father's first marriage certificate gave his father's name wrongly as Thomas when it was George.
George Rushton's grand daughter, Gillian married my nephew Robert Museth