something about the name of Dai Viet and its culture that may be of some help.
(After the king of Dai Viet consulting Qing whether he can use "Nam Viet" or South Viet as the name of his kingdom, officials discussed with the Emperor: )
"The realm of Nam Viet also contains Canton and Guangxi according to the history, which is much more wide than Annan, as Jiaozhi known as formal dynasty's privince, that its king rules actually now. This name is irreverent to the Celestial Empire. This kingdom born from the dust of formal Viet, then controlled all Annam. Considering this, the Celestial Empire has decided to grant it with the name "Viet Nam", meaning that the first and more decisive word inherits it's ancestor, while the second word identifies its tributary status of Celestial Empire, and it's position to the south of Yue/Viet"
Reference:嘉庆重修一统志
Yue and Viet are the same thing but spelled differently in Chinese and Vietnamese. Viet Nam means "to the south of Yue, successor of Annam", which can be understood as tributarya of CE. Nam Viet (South Yue) means "the Kingdom of Viet in the southern part of China" whose claim can reach the Yangtze River at most far. Dai Viet means Great Viet, similar to Great Yuan or Great Qing, while Dai Nam means Great South, claiming as south china against Qing (north china).
All I want to say is that, "Viet Nam" is not that suitable as the name of a new CE dynasty.
Cantonese is also called the local dialect of Yue. Canton, Guangxi and North Vietnam (Jiaozhi) sum up, called South Yue or Nam Viet, or just Yue/Viet in ancient China. This area has been divided from China Authority since Yuan, and the king there claimed all territory of Yue/Viet.
P.S. I don't know what is Sino-Altaic. I don't think it's a good idea to use such a modern and controversial term on historical simulation.