No, although they were killed by injuries from action, they wouldn't be classed as "Kia", as they weren't killed during the war.
A 12 month tour was average. For the US Army, extensions were in 6 month increments. So, for the USA, two tours would be 18 months, three tours 24 months. Other US branches may have been different.
The first military advisors were sent to Viet Nam in 1959 and the last one came home in 1973. The normal tour of duty for a soldier sent to Viet Nam was 12 months. Some served multible tours. In some rare cases the tour of duty could be as much as 18 months.
To simply have served in the country of South Vietnam while serving in the U.S. military services. Many joined the Army, so the initial service was three years. Others were drafted, and had to serve two years in the service. Draftees who came home after serving a year in Vietnam with only two or three months remaining on their 24 month service obligation were given 'early outs.' Others serving from '59 to '75 are considered Vietnam Era Veterans -- serving in the military during that time, but not actually assigned to units in Vietnam.
micrtaumas
At least 6 months.
like years or 15 months
Unless corrected by someone, US Sailors conducted WESTPAC cruises, which may have lasted about 6 months on the gunline in Vietnam. Brown Water Navy sailors manning the Swift Boats and other riverine boats performed a regular 12 month tour. The USN was operating two separate navies in the Vietnam war; Regular warships and riverine boats (officially classified as their "Brown Water Navy").
yes
After nine months, a guard is recognized with a badge signifying service at the tomb.
US Servicemen had been fighting communists in South Vietnam since 1955.
6-12 months