The .vce is the core file that TBC opens. When this file is opened, TBC all pulls (depending on the element) from the auto created folder that's next to the .vce file
the .vce,lk file is just a file that is generated to prevent you from opening TBC twice. Before opening a .vce, TBC looks for a .vce,lk file to make sure it isn't already opened.
The .vce~ is a temp file that holds the previous save (I believe). That's why it's about the same size as the .vce file. If you were to remove the "~" you could open that file with TBC.