Make Bot here bringing answers to some of your FAQs 
If a scenario was paused due to an error and then made inactive, does it require manual reactivation or will it automatically activate after X amount of time?
‘Yes’ would be the short answer here 
To add more detail, it all depends on the type of error. For example, an authentication error 401 or 403 will make the scenario inactive and will require manual reactivation after you have reauthorized the connection.