So now you have established that this Thomas has lived to the age of fourteen.
Sonia, perhaps you know that a Norwegian child would typically be confirmed in the Lutheran faith at the age of about fourteen. Some children did not survive to that age.
This Thomas also goes missing in the census and has either died after his confirmation, or has moved away. He too could have immigrated.
It is key to keep track of the search parameters Jackie used and shared (which is much more information than is usually posted by a volunteer).
There may be further searches in the future, since you (Sonia) are still adding information from Australia. It will be important not to repeat the work that has already been laboriously undertaken to find Thomas Thompson's origins. Thus you will want to be able to report in detail about the ground Jackie has already covered.
Another piece of Australian documentation that is missing is the original ship's manifests for the immigrations cited.
I did email you, Sonia, with the original documents for the 1930 and 1940 census in San Francisco, and the immigration records to USA for Wilhelmine and Margaret May(using my memory here - I think that's what I sent you).