I finally got the Sprites to show.
Just in case anyone encountered the same problem. For me, this is how I did it:
1. Export the graphics & Sprite Collections (including the Data) from Project 1 and Import them to Project 2.
2. In Project 2, select each imported Sprite Collection, Open Editor, and click Commit. You must do this to all imported Sprite Collections.
3. Finally Export the rest of assets from Project 1 and Import them to Project 2.