Does the timeline simply reflect "pointers" in the captured clips? - Yes

After the final edit, can the captured clips be removed? - NO! NO! No! - As an experiment try it out with some stuff you are prepared to rubbish - yeah?

Or must they stay in place until the project is rendered to tape or an avi file? - YES. Look at the size of the VF project file. Very small. Look at the size of the captured work - yes?

If not, must you plan to keep as much drive space for the rendering as the final file is in length? - Yes, preferably a separate Video Projects Drive

Now, keeping the VF file and any associated media - not including the video files - you could then recreate the project, by then re-capturing the footage. Others have many different ways to archive their work. Stand back and be awed! Ho! You minght wanna do a search here on archiving and maybe visit the Veags site for the same - yeah.

BUT NO!!! DON'T DELETE anything until you've finished Printing to Tape, Render to a MAster file or however you get your hard work back out of the PC . . .

Grazie