South Vietnam was considered an ally of the US.
Australians.
China
Great Britain was a "supportive" ally during the Vietnam War.
Yes, South Korea is an ally of the Republic of Vietnam. During the Vietnam War, South Korea helped the United States and the Republic of Vietnam to fight against the communists. The Republic of Vietnam was helped by South Korea, by the United States, by Thailand, by Taiwan, by New Zealand, by Australia, by Singapore and by Malaysia!
Yes
Laos was neutral.
The VC were an ally.
Burma was neutral.
USA lost to north Vietnam not south. The south was their ally.
Nationalist China was an ally but did not send troops. The others were neutral.
Thailand was an ally of the US.