Sorry, don’t know about Louise Landsberger, but John Wylie may be of interest. A John Wylie went from Scotland to Ceylon and married Mary Robb in about 1856 (she was 16). They had 7 children; one of the sons was called John, I don’t know when he was born but it’s a possibility he was ‘your’ John. From a letter I have written by Mary’s sister, John was still in Ceylon in 1916. If any of this fits with your Wylie information, I would be pleased to hear from you.