Prime Minister Mark Carney has said the military is running scenarios in the unlikely case the US invades Canada.
Roughly 20 admirals and generals already have either resigned or been fired since Hegseth took over the defence department.
Major Fred Davenport was awarded both the Distinguished Service Order and the Military Cross.
A law establishing voluntary military service came into effect in January, but protest organisers fear compulsory service could follow.
The Canadian Prime Minister told The New York Times that Canada has considered the remote possibility of US military action.
The prime minister described the risk of an action by the country's southern neighbour as remote, but said "it would be irresponsible" not to prepare.
In a letter to Senator Kirsten Gillibrand, acting Navy Secretary Hung Cao said the crew had adequate mental health support during the long deployment.
Army applicants from Gloucestershire and Dorset say they had been prevented from joining due to what they consider irrelevant or minor medical conditions.
Trump said the updated plans were at the request of the US military and for national security purposes.
