There should not be a problem when a microflow uses other microflows belonging to different modules.
Regarding the error that you’re receiving, you could open the microflow → right click → open properties → open allowed roles property → just check and uncheck the roles and that should work.
This error generally happens when we copy a microflow from other module which had different roles (can be of same name). Although I’m not sure if you copied in this instance or created yourself from scratch.
But hope this helps!