1. the cruise should be in operation although the voyage will be a little shorter.
2. the elctric power voltage in Guilin is 220V, different from Japan's. Usually, the star-rated hotels supply transformer
3. you could convert currency at https://www.travelchinaguide.com/tour/currency-converter.htm
4. just for shopping and food, I think 2000~5000is enough. It is easy to find a Bank in Guilin for money exchange. On the other hand, these hotels also supplies exchange, although the rate is not very satisfied.
5. Please take it easy! This city is safe at night, but don't too late!
6. the local dialect varies in different regions. Anyway, Mandarin is understood well througout these touristy places.