So I’m configuring a service (an automation) which is triggered by an webhook. The automation will process data and then send the requester an email when the job is done.

I want to add a little more feedback to the process for the end user. This is in part to reduce the amount or possible duplicate submissions - As I see it I have a couple of options:

1. Send an email when the request comes in confirming that the request is being processed. Most likely this will be enough. (The user will already get a confirmation form the webapp where they submitted the request)

2. Send an email after a certain amount of time (e.g., 15 mins) in case their job is taking a while or they are stuck in a queue. 
3. Try to detect duplicate submissions and send an email to the user that their duplicate request was cancelled.

As I see it option 1 is the only one which doesn’t require an extra free engine to run another job. Am I missing something?

Are there clever way to do either 2 or 3 without an additional engine?