It's been over a year and my memory of this particular project is not terribly sharp, so with that warning:
1: Not sure if that's a question, if so I'm having trouble understanding it.
2: I believe you are asking when I manually triggered the customerAddressUpdateAfter action. I did not manually trigger the action that I was hooking into - I was just adding additional logic to hook into existing inbuilt triggering of that action by registering hook "actionObjectCustomerAddressUpdateAfter" as well as implementing a function named hookActionObjectCustomerAddressUpdateAfter() with one parameter inventively named "$params".
3: Likewise, I didn't override or otherwise alter the address forms. My plugin acted as a bridge between Prestashop and a custom ERP solution, so all that it really needed to do was to hook into CRUD operations of Prestashop entities and mirror those operations to the ERP system (or vice-versa, but that was actually a distinct extension of the ERP system that resided outside of Prestashop).
What you are doing sounds like you are extending address entities and the interfaces for managing them, which is a little deeper into Prestashop's extension/plugin functionality than I ever had to delve to get my solution running. I will provide advice if I can but it sounds like I dipped my toe into a pool that you're going to be walking in knee-deep.