Hi Georgie,
I am also descended from Emily Lingstrom (nee Couch), but not through her husband, Wilhelm Frederick Lingstrom.
She had a daughter, my great-grandmother, Ivy Kathleen Couch, before she married and I discovered that Emily sued the father, John Campbell for maintenance.
Emily was known as Emily Lynn (or Lynne), nee Couch, in newspaper articles, even though the full name was Lingstrom. It looks like they anglicised the surname. You might have some luck looking for Fred Lynn or Lynne?
Also, I discovered that Emily's parents' names are John and Jane, but I haven't got any further yet.
Here's an article about Emily's death, as an example. You can see that it has her sons Alfred and Carl mentioned, as well as her first daughter Ivy Kathleen Miller, who was married to AH Miller (the secretary and organiser of the Cooee march from Gilgandra to Sydney.)
http://trove.nla.gov.au/newspaper/article/100362127?searchTerm=%22emily%20lynn*%22%20gilgandra&searchLimits=
Lorinda