Unfortunately renaming a file won't work because the state of the file is stored in downloads.dat. That file isn't easily edited.

The result grouping in the GUI is approximate; it tries to groups files that are similar but not necessarily the same, e.g., "File 1.txt" (100 KB) and "FILE 1.txt" (101 KB). LimeWire won't swarm from both files, but it will try them one after the other.

The autorequery feature "canonicalizes" the file name before requerying, i.e., it extracts the most relevant keywords. Any results matching exactly incomplete files will be resumed. Other results may be downloaded anyway.