1. I've noticed the same thing! I suspect it might be an OS X issue. Even if the file is only 60% downlded or so, it will show as total size. I guess it depends upon type of file. Videos & image files have this tendency in many cases. Particularly image files. And sit & zip files also. It doesn't appear to happen to mp3 files, including albumwraps (some of which can also be large around the 300+ MB size.) Perhaps it's related to large sized files. I don't know.
2.
http://www.gnutellaforums.com/showth...&highlight=red will give a clue. You can still resume them to get them started. But just make sure you haven't already downlded them. And Murasame's post on the topic
http://www.gnutellaforums.com/showth...&highlight=red