FCP to Compressor for AVCHD/Pro Res footage

I?ve been combing the web for answers, but haven?t come across one that answers my questions.

FCP 7's Log & Transfer converts the AVCHD footage from a Canon vixia camera automatically to ProRes 422. The original video is 1080i 29.97fps, 1920x1080. The FCP timeline settings are HDTV1080i (16:9) aspect ratio: Square, 29.97, Field Dominance: Upper (odd), Compressor: ProRes 422

I export to QT self-contained ProRes .mov file and bring it into Compressor. Will I get the best quality for a dvd by just dragging the MPEG-2 setting into the batch window, or do I pre-compress to ProRes 422 first, then to MPEG-2? Should the aspect ratio still stay 1920x1080 or should I downsize to 720x480 anamorphic? Should settings be Better or Best?

A few other questions:
Is Compressor better than MPEG Streamclip for this?
When to use ProRes 422, Pro Res 422 LT, or HQ and what is the difference?
If original footage is interlaced, is it better to transcode to progressive, for dvds, or is that just for web?

Thanks,
Nina