Half siblings definitely looks like a good possibility--the cousins look like cousins, the aunt looks like an aunt, and the suspected half sibling looks like a half sibling--all of those people came up in the range you'd expect to see.
Network President Jenny LeFevre, Agent Orange Victims and Widows Support Network, attributes more than 250,000 deaths to Agent Orange, a toxic herbicide the U.S. military sprayed over Vietnam from 1962 to 1971.
Agent Orange and Dioxin Hot Spots in Vietnam. During the American War, US military forces released over 72 million litres of herbicide into the environment of southern Viet Nam in a code-named mission called Operation Ranch Hand that extended from 1962 to 1971. The majority of the chemicals sprayed were Agent Orange in order to destroy forest cover and food crops.