Hello, you may be the best parents in the world, but people will always think in binary terms. I am hapa and my parents are exactly like you and your girlfriend, brilliant people my mother's family is rich and marrying a white middle class man would not have been a fetish or something to get her out of any condition. My parents are still married and together (they are over 50) which is rare.
They are very happy, but my brothers and I don't feel at home anywhere, in Asia we are not considered Asian enough and in Europe we are almost "Chinese" to everyone. It's really terrible to know that we don't fit in anywhere, that we don't have a defined group and that we have to justify ourselves all the time. My parents have a very rich family history and I know all about my 2 cultures which I love very much, but my brothers and I would never be like white or Asian and that plays on our confidence.
I can't advise you anything more, you seem to have thought through your children's education very well, which few mixed parents do. You would be good parents, you will learn the 2 languages, the traditions,... The rest will only depend on the strength of your children, the support of the families and the world outside.