First and foremost, HD DVD is dead, period, DVD is SD 720×480. If you need to give your client HD it needs to be as a file or on BluRay.
Why can you not edit in FCP, but if you are going to edit in FCP you need to transcode the video from the Tricaster to something like ProRes with Compressor. Then do your edit and say the file at the current setting. If you use Premiere Pro you will not have to do the transcoding.
DVDSP needs an m2v file for video and audio should be ac3. We have a ton of post about converting if you need to truly author a DVD.
Also, say you convert the file to an .mov mean nothing, that just means it has a quicktime wrapper. Like telling a mechanic you have a CAR, what kind of car is it.