the Cham and the Khmer
No, the languages between Vietnamese and Chinese are much different. Including the looks, the countries and the citizens are much different. Do not believe those people who thinks that Vietnamese people are Chinese. Vietnamese people are not Chinese. Vietnamese people are just Vietnamese people and Chinese people are just Chinese people.
Indus Valley groups
No
The Nguyen dynasty was the last dynasty of Vietnam. During the early 20th century, a lot of people took the last name Nguyen so that the French won't threaten them because they cooperated with the Nguyen Dynasty.
I don't now at all
there was a lot of gold to find & they had good trade items
Because there was much gold there to find.
there was a lot of gold to find & they had good trade items
because Han is came from Han Dynasty which succeeded the short-live Qin Dynasty that united China.
Vietnamese.
There are Vietnamese people in China but not many.
A range of different groups including the South Vietnamese army. One of the more famous ethnic groups were the Montagnard people who lived in the highlands/mountains.