Haven’t done DVD – Video job in a long time…Workflow questions.

Hello All
Hope you don’t mind the question as its been some time since doing one of these things.

Source is at 1920 x 1080 25fps
Going to NTSC authored DVD-Video for international delivery.
There will be four language streams:
English - UK
Chinese - Mandarin
Korean - Standard Korean
Spanish – European

Now…the master video is in English and once completed we are going to record the other languages using the English version as a reference. (VO talent reading from script and trying to pace things out to the English ref video).

Now, if we time everything the other languages out to the English version (at its master frame rate of 25fps), is there a chance for things to go out of sync once the video is transcoded to the delivery frame rate? (NTSC 29.97fps) Since the audio streams are separate to the video stream.

Should the video first be conformed to the delivery frame rate before doing the VO work?

Hope that makes sense. Any thoughts are most welcome.

Sincerely
Daniel