Sorry for my bad English but:
First, the Vietnamese campaign, is terribly historically wrong. The Trinh lords and Nguyen lords ruled Northern and Southern of Vietnam respectively AT THE ENDING OF THE LATER LE DYNASTY, not before it rose up.
Second, so far there has been no article or archaeological evidence supports the idea of Vietnamese being an archery civ. Even the Vietnamese unique unit, Rattan archer, sounds really unfamiliar to a Vietnamese like me. The word “rattan” is not a Vietnamese word, and it doesn’t even exist on Wikipedia by Vietnamese. Vietnamese history does claim that archers of Dat Viet (medival name of Vietnam) were outperformed by the Mongols. According to Vietnamese history, Dai Viet army had well organized cavalry and infantry, and a powerful naval strength with unique strategy. At the ending of Tran dynasty, hand cannons had been used, and at the end of 15th century, besides of regular sword, spear, musket was a prime weapon of the army. The only period when Vietnamese were good at arrows is Âu Lạc period (257-207 BC), and they were crossbow experts, not bows.
Third, I don’t really understand why Vietnamese reveals enemy starting positions.
Fourth, Vietnamese economy is a agriculture-based (still partly true now), so having no economic bonus about farming is quite not accurate.
So, I’m thinking it would be more precise to change Vietnamese into a civ that uses light cav and inf, and a kind of light warship (link attached below) which is described as “fast as wind” and had “2 machine crossbows”, or “two cannons” (Wikipedia - Vietnamese). Vietnamese strategy has been considering mobility as a major priority for thousands years, so why not?
*I’m attaching only links from Wikipedia, since other sources are in Vietnamese
Trần dynasty military tactics and organization - Wikipedia
Mông Đồng - Wikipedia (Vietnamese warship)