Hey @jhayles,
The reason why is stalling could be because the source site uses an outdated version of Pro. We have mentioned that previously and we demonstrated that updating Pro manually is the solution. You must update the source site first before duplicating it.
Another possible reason why it’s stalling is server configuration from the source server is carried over to our server and there’s incompatibility.
Cornerstone is not installed on your site. If you see Cornerstone in the WordPress Admin Menu, that is normal as Cornerstone now is a general name for our family of builders. You can learn more about that here https://www.facebook.com/yourthemeco/posts/4029224620507666