16:9 in NTSC is anamorphic, so you’ll need to have a monitor that can work in 16:9. If it’s a 4:3 CRT, there is ususally a 16:9 option that formats the image, or if it’s a 16:9 monitor, just set it to stretch the image to fill the screen.
Same with the Quicktime. Open the exported video in QT and hit cmd+j and change the display size to 864×486 (for D1). If you are sending to Compressor though, just compress the 4:3 file and make sure you check the Anamorphic box in the Compressor settings. DVDSP will make let you choose the display options.
If you really just want the video letterboxed and not 16:9, change your sequence to a 4:3 NTSC setting in FCP and add the 16:9 footage. FCP will letterbox.