This would be a case where you want to separate what the characters think their problem is, and what the Author is focusing in on as the source of conflict. This is the trouble with the "Situation" nomenclature, because every character thinks she is in a difficult situation (not saying that's where you're coming from, but this where many others get tripped up).
Undocumented immigrant is the Subject Matter - the storytelling on top of the story structure.
Is the story about the label of illegal alien (Universe), or is it about attitudes about you people (Mind)?
Another way to check is to look at the personal moments where Marta deals with issues not connected to the Overall Story. The "ignoring murder mystery television" sequence mentioned before is a great example.
Lastly, looking at the Concerns and seeing all four at once, which one feels more complete in her journey?
Does Marta personally deal with Past, Present, Progress, and Future? Or does she deal with Memory, Preconscious, Subconscious, Conscious?