OK, situation in Vietnam, as I see it:
1945
everything as in OTL, Japanese surrender, Chinese troops enter North Vietnam
1946
Chinese troops, after a deal with the French, leave North Vietnam, French take colony back. Viet Minh retreats into the jungle. China is in mid of Civil war, so they can't pay close attention on situation in Vietnam.
1947
everything as in OTL, start of guerilla warfare in Vietnam. China is still in their own Civil War, so they don't meddle in Vietnam.
1948
Here comes the major POD. Nationalists win in Chinese Civil War. Meanwhile, war in Vietnam is continued. French organise State of Vietnam ( within the French Union ) with Bao Đai as Head of State.
1949
China is enough consolidated after the Civil War, so they can start meddle into Vietnam. Chinese are not sure what to do. They do not want French retaining their colonies/influence in Asia. OTOH, they are VERY against Communists/Viet Minh. China starts to push for negotiated solution.
Meanwhile, war in Vietnam is continued.
1950
China starts to pressure both sides ( French and Viet Minh ) to try to make some sort of agreement. Chinese ask that the French leave Indochina, otherwise they will start to sent weapons and supplies to Viet Minh. OTOH, they want unified Vietnam, and that means coalition of Vietnamese Kuomintang and other non-Communist parties and Viet Minh, with Bao Đai as Head of State/Emperor in constitutional monarchy. So they pressure Viet Minh to accept the proposal, if they want their help.
1951
Conference of Bangkok. Chinese and the United States are main mediators. They agree that the French will retreat from Vietnam within one year. Vietnam will become Empire of Vietnam, as constitutional monarchy, with Bao Long ( son of Bao Đai ) as Emperor. Provisional Government is formed, with Vu Hong Khanh as Prime Minister and Ho Chi Minh and Ngo Đinh Diem as Deputy Prime Ministers. Power is shared between Communists and other parties, with 50% ministers are from Viet Minh and other 50% from other parties. Elections for Constituent Assembly will be held within 12 months, under supervision of observers from France, China, United States, Indonesia and Czechoslovakia. Constituent Assembly will make a new Constitution within 6 months and elect a new Government. Vietnam will be neutral country, with no foreign military bases.
1952
Provisional Government is formed. French troops leave Vietnam at the end of 1952. Elections in Vietnam are held under foreign supervision.
Cambodia and Laos also became independent states as in OTL.