How can I use WP Empire Builder with a plugin like 1-Minute WP Launcher or WP FreshStart?
The best way to go about it is this:
Install WP Empire Builder.
Upgrade your site to Empire version.
Upload WP Fresh Start or 1-Minute WP Launcher. Check the option that says "Make this plugin active on all sites I create in the future."
Add a child site with WP Empire Builder. Clean it up with 1-Minute WP Launcher/WP Fresh Start.
Add another child site with WP Empire Builder. Clean it up with 1-Minute WP Launcher/WP Fresh Start.