I found some very interesting facts and names from this list of orginal settlers in McLennan county. The family name Heine and Guderian are listed with the Gummelt families. It mentions that they came from Prussia and Galveston. Perhaps Darrel Monroe can help you. Here is his entry. Look under Gummelt Families in Texas.
Gummelt Families in Texas
Author: darrel monroe Date: 23 Mar 2002
Board: Boards > Surnames > Gummelt
I am trying to connect two sets of Gummelt families in Texas. The first are descendants of Martin and Annie Gummelt. Most settled in Washington County and McLennan County. ...