He sounds like a colorful character!
Checking our records here in New South Wales, he's listed in the NSW Police Gazette 15 Jan 1919 under Breaches of the War Precautions Act 1914-1918 - "American alien Gerard Peabody who, on the 24th September, 1918 gave change of notice of abode...but not further reported. He is 19 years of age, 6 feet 1 inch high, medium build, dark brown hair, brown eyes; a seaman. Arriving in Sydney by the American schooner "Gamecock" on the 30th November 1917. ....was accompanied by a young woman - supposed his wife. Report if traced".
Our BDM records show he married in Sydney twice.
7 Jan 1918 to Mabel Lillias Pearson, then 24 Dec 1919 to Rosella Craggs
So it appears he may have talked up his involvement with the Royal Air Corps and the Mounted Police!
There are no local records of him divorcing Mabel, so it seems he may also have been a bigamist?
He and 2nd wife Rosella (Rose Ella) left Sydney on 1 Mar 1920, transiting through Honolulu on 20 Mar 1920. He listed his address in the US as 1144 Harvard Ave. Nth., Seattle. Interestingly he recorded his birth date as 26 Feb 1896, when US records show this was actually 26 Feb 1900. Avoiding Australian authorities?
There are 2 Ancestry family trees that show a great deal more about Gerard, if you have access;
https://www.ancestry.com.au/family-tree/tree/73944959/family/family...
&
https://www.ancestry.com.au/family-tree/tree/73092573/family/family...
Cheers, Mike