Here is what you could do.
create everything without pipeline active periods
When you want to run the demo update active periods to dates in the past
If you want to run again, update to another date in the past
Updating dates via Powershell would look something like this
Set-AzureDataFactoryPipelineActivePeriod -DataFactoryName $DataFactoryName -PipelineName $PipelineName -StartDateTime $DateInPast -EndDateTime $DateOneDayLessInPast -ResourceGroupName $ResourceGroupName -Force