Johanna Bren is a mistake in writing, happened in USA (similar Denkinger or Denkniger). Her name in Germany and born with this name was Elisabeth Johanna Böhm.
Elsa her daughter, and halfsister of your grandfather Julius Kaltenegger visited us in Germany in Munich about 1970. I then was a child and made my first steps in learning English and after I wrote letters with her until she died. Elsa lived and died in Pasadena/California. My dream was to visit her once, but she died before I was able to do that.
Very new and interesting is, that Julius Kalteneggers father was Ludwig Kaltenegger. So Johanna Böhm must have been married to Kaltenegger. May be he died early, cause Johanna married again Mr. Hofmann.
My grandfather Karl Engelmann is son of Johanna and her first husband, Heinrich Engelmann, marriage 1887.She was divorced 1898 in Munich,Germany.
Birth date of Elisabeth Johanna Böhm is: August 02, 1864. I do not have the date of her death.
Many regards and thank you for the new interesting informations.