Hi!
Sorry for the delay, we were investigating this use case.
For the given scenario, you can download the 'Event - Searched Flight' using our API here: http://support.wizrocket.com/events-export-api/
The query will return the data (emails) of all users who performed said event Searched Flight in a JSON object which you can use to send out emails from your system. In this case you will explicitly update prices for the flights searched yourself.
We're working on something similar to the scenario 1 you mentioned, you should have an update when we have it.
Thanks,