This tutorial consists of 2 topics:
1) LIGHTWAVE: How to set up render passes using a free, open source plugin called Passport.
2) BLENDER: How to take advantage of Blender's robust compositing toolset to work with your Lightwave render passes.
While this is a basic-level tutorial, I am hoping it serves as a stepping stone for people who need some help with compositing. This tutorial assumes you know about PNG alpha channels.
NOTES ABOUT PASSPORT:
-The render passes save with the scene. Under the hood I think the .lws files are generated as needed based on the current .LWS's data. You do still have the option to save out the individual pass .LWS files though.
-Sometimes the plugin can misread a scene's objects and give errors. Restarting Lightwave usually fixes this.
As a side note, one can use the Buffer Saver plugin to generate things like depth/specular passes pretty easily. This doesn't work with Passport, but I have still found it handy.