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.
The U.S. government used 15 different herbicides, collectively known as Agent Orange, from 1962 to 1971, as part of its war in Vietnam to deny the enemy forces jungle cover and to destroy crops to drive the peasantry into refugee camps or cities.