Hey Kleber!
Thank you for the questions.
About Ruby Trailblazer. No, I would say these are different things. Trailblazer looks like a general framework for both domain and application layer, while ALF is only about the application layer. In Trailblazer's abstraction, I would say, ALF is somewhere between "controller" and "operation" - it's a way of calling a sequence of operations. ALF is closer to what we usually call "use_cases" or "orchestration" object - the piece of functionality that calls domain models and actions.
About BPMN. Not sure if we need such a complication here. ALF is more on the engineering side rather than on the business side. ALF has just simple control-flow abstractions. But even these abstractions can be easily perceived by business folks.
And finally "All of that, as you could assume, is me trying to relate it with something I already know(at least a bit) so I can get ALF's idea easier."
I think that you are trying to compare ALF with other frameworks that are usually "full-stack frameworks" in the sense that they provide abstractions for many (all) layers of a program. Like Phoenix which gives Schemas, Contexts, Controllers, Views. But ALF doesn't force your decision about Domain Layer or Interface Layer. It's just about a thin "application layer" that defines the "stories" of your program.
I actually can understand your confusion, in our software, it's usually quite hard to separate domain and application layers. I should definitely write an article about that! :)