QR Code: The documentation for blockchain.info's receive API is a bit lacking. The PHP example code includes the following, which gets turned into the QR code:
Anonymous: I don't think the anonymous feature works the way you want. I think it's meant for you to receive an anonymous payment, rather than the sender paying to an anonymous address. However, that doesn't seem very useful... not sure what their intent is.
BTW, I decided to scrap the JS button code and implemented my own PHP processing. It still calls the blockchain.info API to create addresses and set the callback, but it does not rely on any JS. All the logic is server-side.