I think a lot of people were confused with all those births but there were 3 marriages of a Thomas Greentree to Catherines. One in 1867 to Katherine/Catherine Hobbs and another in 1879 to Catherine Smallwood. I found on obit of Trove which takes care of a number of the ones who belong to Catherine Hobbs.

There passed away recently one of the oldest identities of Rooty Hill, in the person of Mrs. Katherine Greentree, wife of Mr. Thomas Greentree, Deceased, who had reached her 84th year, was a native of the Hawkesbury district, and prior to her wedding was Miss Hobbs, a name well known around Windsor.
With her husband and a young family, she went to reside at Plumpton over 40 years ago, and, during that time, had been one of the most respected residents.
She is survived by her husband and a family of grown-up sons and daughters, including Messrs. Herbert (Auburn), Frederick (Rooty Hill), George (Riverstone) (I presume this is the David George) , and Mesdames Erwin (Ada) and Curry (Emmeline) (Wentworthville), Halligan (Hilda) and Honeysett (Plumpton), and Walker (Ruby) (Enfield). (I couldn't find the Honeysett one)
In addition she leaves a large number of grandchildren and great-grandchildren.
(Newspaper dated 15/3/1924 - Cumberland Argus etc – Parramatta)