Short answers, pulled from the story.
Seventy dissident Cambodians gathered in Kratié Province on the 2nd of December 1978 to begin a new political chapter. They met near the border with Vietnam at a location now known as Cheung Khlu, Pir Thnu, Snuol district.
Heng Samrin served as chairman while Chea Sim took the role of vice president and Ros Samay acted as secretary general during these early days of organization. Hun Sen joined the council as Foreign Affairs minister under Heng Samrin's chairmanship.
The Kampuchean United Front for National Salvation provided political cover for the Vietnamese military intervention into Cambodia. This heterogeneous politico-military organization legitimized the invasion that precipitated the defeat of Democratic Kampuchea.
In 1981 it became known as Kampuchean United Front for National Construction and Defence or KUFNCD. On the 29th of April 2006, the fifth congress held in Phnom Penh changed the name again to Solidarity Front for Development of the Cambodian Motherland or SFDCM.
The Kampuchean Federation of Trade Unions claimed 62,000 members by December 1983 alone while the Kampuchean Revolutionary Women's Association claimed 923,000 members as of October 1983. The Kampuchean People's Revolutionary Youth Union served as a reservoir of candidate members for the KPRP.