I can answer this question for Vietnamese traditional wine production. This is not limited to just rice wine as Vietnamese brewers have been known to use herbs, leaves, and roots to concoct what was originally medicinal drinks which could be considered moonshines. This is a nice brief post about different types of traditional alcoholic beverages in Vietnam. Most of the sources listed here will be written in Vietnamese and I suggest you should run them through Google Translate (which is pretty accurate lately - up to 70% I say).

Booze was, is and will be a big part of Vietnamese culture. One of the early written history records mentioned a usurper by the name of Đỗ Thích who murdered the king and heir of the Đinh dynasty while they were pissed drunk back in the 8th century. This is a post about the mentioned incident and this is a post about the historical development of the brewing culture in Vietnam.

In Vietnam, rice wine has many names (based on the type of rice which is used to make it). It is often called rượu đế, rượu gạo (rice wine) or rượu nếp (glutenous rice wine). Rượu đế is the oldest name which originated from the winemaking artisan villages located in Northern Vietnam. There are a lot of writings about this matter, unfortunately, it is not widely sought after by international audiences so most texts are still written in Vietnamese. Perhaps I will sit down and put together a more thorough answer in the future.

Thanks for your interests though! I hope this answered a part of your question.

Absolutely. And you can kinda-sorta get close to what it might have been.

In East Asia, not only is there evidence, but you can have something of a sample of one potential form (albeit heavily modified). There's a guy, Dr. Patrick McGovern, who's spent much of his career looking at early evidence of alcohol production, and the beer Chateau Jiahu by Dogfish Head is based on his analysis of residual markers of drinking alcohol on Chinese pottery found in Jiahu, modern Henan.

If you're interested, have a look at Fermented beverages of pre- and proto-historic China on which he is the first author. This is the abstract:

Chemical analyses of ancient organics absorbed into pottery jars from the early Neolithic village of Jiahu in Henan province in China have revealed that a mixed fermented beverage of rice, honey, and fruit (hawthorn fruit and/or grape) was being produced as early as the seventh millennium before Christ (B.C.). This prehistoric drink paved the way for unique cereal beverages of the proto-historic second millennium B.C., remarkably preserved as liquids inside sealed bronze vessels of the Shang and Western Zhou Dynasties. These findings provide direct evidence for fermented beverages in ancient Chinese culture, which were of considerable social, religious, and medical significance, and help elucidate their earliest descriptions in the Shang Dynasty oracle inscriptions.

Further studies have also been published tracing the transmission of alcohol in the region.