Construction Bank is part of a global ATM alliance or something. So you don't have to pay ATM fees at those banks. But you need to search online for the list of banks. The folks in the branches don't see to know about it.

I tried using my China Merchants Bank union pay card in Thailand 2 years ago. No way.
Construction bank may not charge ATM fees, but the probably mop this up in the exchange rate. Be careful there is often a double exchange rate as RMB is not a tradable currency. In most cases money you draw outside China will first be converted to USDollars, and then USDollars to RMB. Remember that yo won't get the prices quoted on finance pages either. There are buying and selling rates.

RMB can be exchanged in most places in Laos, Cambodia and Thailand. If no other place then exchange them immediately upon arrival at the airport at your first destination. At Bangkok airport, RMB is accepted for exchange easily and readily by every moneychanger. I wouldn't bother buying USD prior to travelling to these countries, unless Cambodia is your first destination. The USD is the main currency in Cambodia, not simply a reserve currency. ATMs in Cambodia dispense only USD and all prices are quoted in USD. The local currency, Riel, is only ever used for small transactions or in the countryside and few people ever use Riel for anything costing more than about US$5. Thai Baht is accepted in western Cambodia for all transactions.

In Laos, the Thai Baht reigns supreme although the government is trying to get all merchants to accept only Kip. USD can be used in the bigger cities but it's better just to use a combination of Baht and Kip as dollars are really only accepted in tourist related businesses such as hotels, restaurants and for large purchases.

I found that while there may be moneychangers that don't change RMB in Vientiane, there are plenty that do. I think it's more of a hassle trying to purchase foreign currency within China than trying to change RMB outside of China.