What was the reason for Aisha, may God be pleased with her, requesting to be buried at night?

Burial at night is permissible out of necessity. Fatimah, may Allah be pleased with her, passed away on the night of the seventeenth of Ramadan, after the Witr prayer, and was buried at night. Perhaps this was so that her burial would not be delayed, or because it was more concealing for her, or to demonstrate the permissibility of burial at night.