Yep, the parents know; they sent the list around. I saw a list online of a survey of tweens saying what they want for Christmas, and, yeah, these asks seem to be in line with the general tween expectations.
1. do you expect a thank you card if you gave a gift in person and the recipient asked them then?
No. In person thank you is good enough for me.
2. do you get gifts for siblings?
No. We sibs started doing kids only Christmas a few years ago.
3. what kind of gifts do you get for your SO?
It varies a lot, but we typically do get each other one “big” gift. Our birthdays are around Christmas, too, though, and sometimes we take a trip or something as a joint birthday gift. If we do that, then the Christmas gifts are smaller.