USB: Are any Windows / Mac drivers or software required for the Dante AVIO USB Adapters?

No.

Dante AVIO USB Adapters are USB audio class-compliant, and work with any OS that supports class-compliant audio without the need to install additional drivers. Windows, macOS, Android and iOS all support USB audio class-compliant audio.

ChromeOS technically supports class-compliant USB audio – however, Dante AVIO USB Adapters have not been extensively tested on this platform.