"Sankyu" was a good choice. I assume it's similar to what we English/Chinese speakers refer to as "Chinglish" which is basically a mix of languages.
Xie xie - thanks in Chinese.
Thank you - Obv English
Sankyuu - It's kind of a youthful and informal way
It's a cultural thing which doesn't translate well, but I guess it's like me saying "gracias~!" to a fellow non-Spanish speaker.
The translation of page 9 confused me though. Connecting the verbally spoken words it becomes: "Do you like them? Donuts" "Not really, I just... about as much as I like you, maybe". Which seems rude, lol.
I interpreted it in my mind as "I just... like you" or "I just... like seeing you enjoy them".