The important question to ask is "Is it likely that this establishment has a working card reader?"
If it's a larger place, in a bigger/more international city, the answer is more likely to be yes. I just used a CSR at a hotel and my friend used a US Amex at a restaurant in Beijing.

This is my preferred transaction order:

• Directly using CSR on Trip.com or in person. Codes as travel so 6% rewards
• Directly using CSR on Ctrip.com. Codes as travel so 6% rewards minus 3% fee = 3% rewards. Sometimes this is cheaper (including the fee) than Trip.com for plane tickets.
• Using Alipay with CSR for small purchases. Codes as a general purchase so 2% rewards.
• Using ICBC (USA) Preferred UnionPay Gold Card. 1% cash back.
• Using Alipay balance, cash, or local bank card. Assuming you aren't getting charged ATM fees or can get a friend to fund you, this is net even.
• Using Alipay with CSR for larger purchases. 3% fee charged but 2% rewards = 1% fee.
• Using Alipay with TourCard (let's assume it works). 5% fee charged but 2% rewards = 3% fee.

Basically, if they have a card reader, I'd rather use a different card than the ICBC US UnionPay as it has better rewards.
I'm sure there's some card readers where they would take my UnionPay card but not my Visa card, so I might try it there.

Re: the BoCHK Type II account, I don't have any experience so I guess you just have to try it and see if it works.

Answered above. You can't transfer to a friend with the Visa card. Only with existing balance