Engagement API real time possibilities

Hi.
I am integration developer. I have learned documentation about PUSHing data from external system to Bloomreach via Engagement API. And i have not unambiguous understanding is there ability to pushing new customer data via Rest API? There is method to create new events, but not new customers. Should i transfer new customers via imports only?

My case is to import customers and events in real time (or close to it) and to create communication scenario. I have not found documentation about reaction time parameters.
Exapmple:

  1. Import new customer.
  2. Pushing the event.
  3. Perform scenario with event-based start and webhook reaction result.
    How fast System will generate webhook?
    What is fastest way to import customer data to Bloomreach?
    Is System designed to such cases with real time reaction?