[Johan K]

There is no modding support in CoE3 right now. It will probably be added, but maybe not until after it has been released.

The cosmology will be similar to Dominions, at least the void and horrors will make it into CoE3. Nations are not the same though. CoE is more about a powerful character like the necromancer, he does not rule a large nation like the pretender gods in Dominions.