Is Bruce Wayne still Terry McGinnis's biological father? / Damian Wayne Question

[Mat001]

Assuming you're right, does this mean that Earth-12 is officially the DCAU?

For all intents and purposes, yes. One very similar to the animated continuity, but with additional stories never covered. It's the same way in the "Superman Beyond" series, that has references to the main Superman ongoing such as Zod, who did not exist in the DCAU.