Yes, the three women you mentioned were the daughters of Thomas Walter Shelley. William M. Shelley's father was John L. Shelley. John L.'s father was Peter M. Shelley, Sr.
Timothy Carpenter Shelley's father was Simon Peter Shelley. Simon Peter's father was Daniel Shelley. Daniel's father was Peter M. Shelley, Sr.
So it was all in the family just as you thought. There were also some related Shelley's who settled in Blanco Co., Texas.