In recent versions, "untitled" is no longer evident. The export title will mirror the SEQUENCE title, as shown on the tab. Rename it there and the export name will follow.

As for stabilization problems, try setting the Source Pixel Aspect to Standard NTSC if that's not already specified.
Your 720x480 does indeed load as 640x480 unless first converted to WMV by another app.
The only shortcut keys in VP trigger effects, AFAIK, so cannot provide info on your last query.