Michele, There is an Anna Reiss who was born about 1864 and died in St. Louis on April 15, 1899 of some kind of convulsions.At the time of her death her residence was 519 Koeln (?) Avenue in St. Louis.She is buried at a Catholic cemetery (Mt. Olive) in St. Louis but it appears no one is buried with her.
The birthdates for Richard, Mary, and Arthur appear to be Aug 1894, Jan 1897, and Nov 1897 respectively according to the 1900 census.
I assume you know that Erhart (Erhanet in 1910) was boarding in a home on S. Broadway in 1910.
Do you know if all of these Reisses died in Missouri?I have a St. Louis Reiss connection but they came in the 1850s.