If you have a long, quiet day at the office to kill, consider reading this thread:
http://forum.videohelp.com/threads/3...PEG-2-encoding. It covers this and other issues pertinent to working with multiple sources of the types you mention, such as taking into account DV vs. MPEG chroma placement, translating between the SD Rec.601 and HD Rec.709 colourspaces, the luma (and perhaps chroma) correction you mention, etc.
For what it's worth at this point, for interlaced material the most important rule is always to deinterlace before doing ANYTHING that changes vertical geometry (e.g. resize and crop), and/or that makes assumptions about vertical information being from the same point in time (e.g. subtitles) and/or is generally interlacing unaware. For example, denoising interlaced material is debatably damaging - spatial denoising will spatially blur information between fields originally from different points in time, and temporal denoising will similarly not account for true movement between fields. In various threads (if not in the one above) jagabo has explained why not even separated-field work-arounds are generally suitable.
The filter sequence you suggest seems largely safe from that point of view, except that some purists would argue that giving the deinterlacer less-than-original field information after levels and chroma correction is sub-optimal.