In case you want an ESL's opinion, here it is (I haven't read the other posts yet):
Question 1:
"Clark ran his fingers through Lois's hair and whispered sweet nothings in her ear." Comma and "and" don't go together.
Question 2:
Neither. It's not about the comma, though, it's that "Lois did sth... and she did sth else." I think that 'she' on the second sentence is not necessary. Otoh, if you really need to draw the attention to her (which seems pointless in such a sentence, but anyway) I think you should use a comma despite the 'and'.
Question 3:
Both. With comma, because the subjects of the two verbs is different. Without comma, because you've used an 'and.'
Question 4:
"After he kissed her, Lois's eyes popped open in recognition. Superman!" I have no reasoning for choosing this one, other than not using a comma makes it sound weird to me. <shrug>
Question 5:
"I notice goofs but it really doesn't bother me, especially if the writer is consistent." Besides, although I generally trust my insticts and my language ability, on some occasions I just can't be 100% sure.
When I write, I usually put a comma where I'd put it if I had to take a short pause while I said out loud the sentence. I've never had problems with my commas in Greek. Where English is concerned, though... it makes me wonder that I've never misplaced a comma in composition writing in English, but I sometimes do misplace them when writing fics.
See ya,
AnnaBtG.
