Once a job is completed, I cannot create a timesheet for it (it didn’t show up on the “All” selection).
In this case, you will need to use the technician interface. Once you have logged in, return to timesheets app, find the job that you want to add another timesheet for, click on view details, and [...]
The Stat Holidays are maintained under Settings > Calendar. With this, both the scheduler as well as dispatch will show Holiday.