Your questions about SoFi Hong Kong are answered here

Cash account members can trade 40 fractional stock symbols (more coming soon) in the SoFi Hong Kong app. The selected stocks are on the S&P 500 and/or NASDAQ 100 Index list which includes big names such as AAPL, AMZN, GOOG, NFLX and TSLA. In the app, you can search within the “Fractional Shares” collection for eligible stocks that are available for Fractional Shares trading.