How do you retain and instill an ethnic identity from birth when living in a foreign country?

I’m not going to speak to the details of the question, but to the general question: how to help instill your ethnic identity abroad, in a child whose identity you have some say in. (If you don’t have a direct say in it, Andrew Crawford’s answer applies: be a good role model.)

• Acknowledge that the child will have the identity of the country they are brought up in, and that identity will ultimately prevail. You can cocoon the child a fair bit before they go to school, and to some extent even after. But if you get too defensive about your ethnic identity, that will end up backfiring in the child’s teens, and your cherished ethnic identity will be something they rebel against, reject, flee from, and ultimately resent. You don’t want that.
• Immerse the child in the culture of your ethnic identity at home. That means TV and books and talking the language at home and little songs and games, and trips back to the mother country. Try not to convey resentment or superiority over the host culture: that will backfire too.
• Immerse the child in the culture of your ethnic identity outside of the home. That means hanging out in the local ethnic community, and building a store of fond memories and associations. It means the culture will be real and lived for the child, not a mere abstraction or playacting at home.

The way to instill your ethnic identity is to build fond associations of family and rootedness and affect in the child with that identity. And even so, being Greek in Melbourne in the 1980s was not the same as being Greek in Athens in the 1980s. Being Greek in Melbourne in the 2010s, even less so. It’s a losing battle. But by being positive and warm about it, you can make the loss more gradual, and more reluctant.