Using CLI tool or Administrative Console is not possible at this moment to check if a custom added module was added correctly, especially in domain mode. The only alternative available is to add host per host. This approach takes time, and for unused users there isn't some visual (GUI) to help them.

JBoss CLI approach:
module --add --source=jar1,jar2 --target=/path-of-module --host=your-host OR module --add --source=jar1,jar2 --target=/path-of-module --host=all (deploy the module in all hosts that belongs to the domain)