Renaming a file should be harmless. Unless somehow the extension got changed. Also, renaming a file invokes permission issues.
I think you lost the extension when you renamed the files.
Can you provide some more details? Why did you have to rename the files to build a list? You can make a list of files without actually renaming the files shirtsleeves. In fact, you can have multiple lists of the files by categories. These are called playlists. Or. you can have a folder of shortcuts. Or even shortcuts without a folder. You can rename shortcuts.
Suppose you have a song named:
I Love The Rain, Alice Cooper
In the came folder you could create a number of shortcuts to the same file and rename each.
Shortcut I Love The Rain, Alice Cooper(1)
Cooper, Alice - I love the tain
Alice cooper, I l Love The Rain
Rain, I love - Alice Cooper
Just a suggestion. Renaming a shortcut does not risk the original file. An it is more versatile.