Looks like you are stuck where we're stuck, at Henry Kahler & Elizabeth Schleining. We do have a Gertrude Glanz Reutter as Elizabeth's mother but no birth/death info. We're pretty sure she was in USA before or at the same time that Henry & Elizabeth came to the USA. Settled around the Hastings, NE area. Died in that area or maybe Sutton.
Some of the info my Dad had on the Kahler family came from a Virginia Lakin either here in Lincoln or out in York, NE. I'm not sure if she's still alive. She is a daughter of Magdalene Kahler, another sibling of your John Conrad and my Emma Marie Kahler. Her priority was trying to record as many descendants of Henry & Elizabeth as possible.
I'm going to try sending you a private message via ancestry.com with a picture.