In essays 5 and 6, I didn't mention the two other students. Essay 5 got 5.0 with 119 words (1 paragraph), and essay 6 got 4.0 with 111 words (2 paragraphs). There were no grammar mistakes in either essay.
I'm not deliberately trying to use academic vocabulary, but it would interesting to see what would happen if I limit myself to short, non-academic vocabulary.
Also, ETS has a new YouTube video on the Academic Discussion task:
ETS's descriptions of the scoring system for the academic discussion is better than it was for the independent essay, and much better than the speaking rubrics, but this topic deserves a blog post of its own. You can download the pdf of the writing task rubrics here.