在內地用唔用到香港hsbc account的網上銀行做轉賬&交易買賣港股呢?

可以處理到香港hsbc開的account
yes, you can
whereever you are in the world (including China), as long as you can have the internet access, then you can log on to your hsbc online banking to process whatever you want (including transfer, check your account transactions/balance, and buy/sell stocks in the market)

同埋要可不可以/合不合法買賣港股?
yes, if the stocks already listed in the stock market, you can
but remember one thing, if you would like to purchase IPO, you need to read the regulations/conditions per IPO, some of them that if you are physically outside HK, then you cannot process the IPO application (that listed in the Terms & Conditions)

No problem with HSBC account, it can be used in any part of the world including China as long as you can get online

只要上到網便可以連線hsbc account的網上銀行做轉賬&交易買賣港股啦~~

我現在都是這樣做的。