On another ML-website, I think it was moonlightingatomicshakespeare.com, I read that the mother, you know the one who tells her son to do his homework instead of watching ML, could be played by Cybill..
I checked on IMDB, but couldn´t find anything about this. I found the boy, though.
But then when I watched it, it really didn´t feel like her. The voice was especially wrong. But I guess it could be her. Would really like to hear (or see) your take on this.
I also read something similar, JKalen. Having recently watched this episode I really don't think it is Cybill.
For a start, I think she would have mentioned it or Jay Daniel would have in the DVD commentary.
Secondly I agree with you that it doesn't sound like Cybill Shepherd. Thirdly, I think the Mum is the wrong 'shape'. She seems more angular than Cybill who is more curvaceous. Also her hands, which are quite noticeable as she places them on her hips, don't look like Cybill's hands - they're too thin and bony.
Lastly, I don't think Cybill Shepherd would have had time to do those bookend scenes as she was way too busy doing almost every other scene in the show!
Anyway that's my take on the question for what it is worth.
I didn't watch from the begining, so I saw only her legs while sitting on armchair (?) at the end. And I thought it might be Cybill (they have similar legs). I didn't pay atention on voice because my mother was watching with me and she was talking something. But that would be pretty good to see Cybill in that role - like mother. That would be simbolistic (I didn't write this regular, I wanted to say that role would be great simbol)