Non-duality, in this context, also means that nothing is separate from the Void. In strict terms, nothing can truly exist apart from it. As you said, the Overvoid is an indivisible whole. However, it doesn't necessarily prevents expressions, manifestations, or functions to exist within it. Across Morrison, DeMatteis, and Vertigo, the Void represents the true extent of God, within which both existence and non-existence are encompassed. Concepts such as creation, beings, and events are part of God’s self-expression or dream, meaning they arise within Him without forcefully violating His non-duality. Most importantly, Grant Morrison doesn’t always strictly adhere to real-world science or philosophy: he draws great inspiration from them, incorporating elements into his own cosmology.