I got some answers of the rust community @twitter :) but still the channels remain a mystery :) I am not sure most likely I have to change the whole structure and architecture of the application.
The core issue I got is that even if it take the Addr<ActorA> I have to most likely do some Box magic because I have to pass ownership without a specific lifetime which means ... 'heap time' and lifteime issues.
Usually you could just 'move' the ownership but since the actor contains Hashmaps in the state and hashmaps are on the heap. Which implies they cannot implement the Copy-Trait because the Copy-Trait is restricted to the stack.
And I need the Copy-Trait because esp in concurrency there most likely should not be shared state .... anyhow this is currently a bit frustrating but a good learning experience.
So I think I will exhaust myself for ~ 8 more hours and after that I will likely go to my whiteboard and try the feynman approach of solving problems.
^^ ... I guess this will be my sad logbook of why actix hate me anyways ;D ...