The problem is NTSC DVDs take up more space on a DVD (4% more). If you are near the limit of the DVD's capacity it may not fit.
Also, there is currently no automated software to do a complete DVD for you, only the movie (and quality will be questionable).
An important question is, is there speed up in the audio or did they pitch shift it?
If they pitch shifted it, when you slow the audio to match the video you will butch everyone up.
If you want to build the full DVD using your raw menus and converting to NTSC, doing it all manually is still your best way to go for the movie as well.
Don't be fooled by the few saying "I have a PAL player", PAL DVD players are damn hard to lay your hands on in the U.S.
Short of playing on a PC those of us over here will have difficulty watching your edit.
The steps:
Encode video with frame rate of 23.976 at 720x480.
Apply 23.976 -> 29.97 pulldown using DGPulldown.
Re-encode audio in BeSweet using the 25 -> 23,976 conversion option. (Assuming the audio was sped up and not shifted, this will bring the pitch back to it's original)
Rebuild the DVD.
You will need to do this for all video and audio content and re-author the DVD. You will not have sync problems doing this, I guarantee.
On another note, I'm curious if you've seen ADM's T3 edit and if that will influence any of your work.