OK. I've done a little digging and there are a few things to explore.
First off, you can use DVD Studio Pro that comes with Final Cut Studio to create a DVD. You don't have to use iDVD or iMovie. (In fact, iMovie cannot create a DVD by itself, it will send the video to iDVD anyway).
Looking at your movie properties, the original footage is from graphic files, right?
In which case you need to be aware that the dimension of the graphics file need to be different to correspond to the pixel aspect ratio. Basically, you need to adjust when working with still images, for pixel aspect ratio differences between the computer, and TV. For NTSC 16:9 the dimensions should be 864x480, this is because the computer uses square pixels and video uses a different pixel system. The pixel aspect ratio will then become 720x480 which is 1.2.
Your file is slightly off the above.
In fact, bear in mind that often Quicktime won't display 16:9 correctly, so don't use it as your judge - the video will still be ok though.
I'd also recommend that when you export your movie in Final Cut Pro you choose Export to Quick time and set the compression settings as Current settings. This is the highest quality for your movie. Let DVD Studio Pro deal with the compression later.
OK, so now you have your movie file...
Open DVD Studio Pro (in your Applications folder) and close any projects.
Go to DVD Studio Pro > Preferences
In the "Project" tab set the DVD to SD DVD and the Video standard as NTSC.
In the "General" tab set the display mode for menus as 16:9 letterbox.
In the "Encoding" tab make sure you're in Mpeg-2 SD mode and set the aspect ratio to 16:9 and the Mode as Two pass VBR
Lastly, go to the "Simulator" tab and set it's resolution to SD and display mode to 16:9.
That's it, open a new project and import your movie. You should be good to go now.
Do let us know how you get on & of course if we can help you further.
p.s. sorry for the length of this reply! :-)