Final answer:
The text provided does not contain enough information to answer the question about the surprise visitor Laila and Mariam find upon returning from visiting Aziza.
Step-by-step explanation:
The surprise visitor that Laila and Mariam find awaiting them when they return from visiting Aziza is not explicitly mentioned in the text provided.
To accurately respond to this question, the context of the novel and the specific characters must be known, but the provided excerpts do not give any details about Laila, Mariam, Aziza, or the surprise visitor.
To offer a detailed answer, one should refer to the novel 'A Thousand Splendid Suns' by Khaled Hosseini, where these characters originate from.
The answer typically requires identifying the character who re-emerges in the story, where they have been, and the implications for the main characters, Laila and Mariam.