I was there last month and it was almost impossible to get money on your WeChat account without a Chinese bank account. It was easy to fund my Malaysian WeChat account but the balance isn't transferable or usable in China.

There's currently one remaining loop hole I know about which is to pay someone to send money via a red envelope / hóngbāo but it's getting increasingly harder. It's already asking you for a passport and right now it still works even if you cancel that but probably not for much longer. You can do that either if you know someone, ask someone in a store if they do it from their personal account or through some websites that take PayPal but with a hefty commission usually.