Renaming source files without breaking link in Premiere?
I figured it out! It was super easy.

I used Adobe Bridge to batch rename. Very importantly, I left the preserve current filename in XMP metadata option checked. 

BUT before clicking rename, I first clicked preview and exported the CSV file and saved it somewhere safe. This file will help you remember the original file name. In this instance I will know that file 001.png was renamed to 120.png. This is very important.

Now in Premiere, all your renamed files will go offline. If all your files in one location on your drive, this next step is very easy. Just link one file and if you can't remember what you renamed it to, the beauty is that you can quickly search your CSV file in many ways like excel. Then just relink your file to the renamed file that way. Premiere will recognize all your other renamed files because you preserved the XMP meta data. And that's it!