Hi
The problem with Streamclip doing the PAL>NTSC conversion is that its just an interface for QuickTime, and QT makes 29.97 from 25 by repeating every 5th frame – not very pretty, if your smooth pans matter to you.
First transcode your PAL to a proper frame-blended NTSC movie – not NTSC DV as that has a 4.1.1 colourspace, not very compatible with a DVD’s 4.2.0.
The Nattress Standards Converter will do this in FCP, or you can do it in (more slowly) Compressor, using the preset to do this, with Frame Controls options to give you frame/field blending.
Then use a Compressor DVD preset to turn the resultingNTSC file into an MPEG-2 file for DVD SP.
In standard def anamorphic is just a flag setting, so your 16:9 transcodes will only look the correct aspect ratio in a program that compensates for this – QuickTime Player doesn’t.