How to use Event Streaming for consolidation of accounting for multiple child companies

I am looking at the Event Streaming feature that was introduced and I believe it can be used for accounting consolidation for multiple companies.
For example, I have:
(1) Holding company A
(2) Child company B
(3) Child company C

Am I correct in assuming that if I want to do just consolidation in accounting, I just setup the Account DocType in company A to subscribe to both company B and company C, so that it can do the consolidations?
Do I also need to subscribe to all the related Links as well?

Is the Event Streaming done using Redis in the background?

In the company creation, I’d make the holding company the parent of each of the children. That is enough to consolidate your accounts