Yeah, tutorial leaders are the only ones as far as I'm aware. And then the faculty member(s) who write your Dean's letter will be the only ones to see the evaluations. Students get to see their evaluations. There is no mention of test scores etc. in your evaluation.
Hmm, to be honest I'm not sure when it was explained, but if you dig deep enough in the HMS policy books you can find it although most of us learned from 2nd years or one another, and faculty have gone over it a few times at various points.
It sounds like it might be important/serious and I was a little anxious about it at first, but now I never even think about it. There are 2 sections, one for comments including suggestions for the future, and another that is comments that can be used for the Dean's letter. So the comments that make it to the 2nd section are almost always good comments, even if you weren't a great tutorial student for that block.