That is some great info, so it really only leaves 16 as a question and what the 'na' is doing to Shiruko, which is well beyond my capabilities. I thought maybe at first it was another typo or just written wrong (like March and Fanfare both have the extra 'a' in the katakana for some reason) but with all these weird nuances maybe not.
Calpis looks absolutely correct:
http://kimigayosubs.weebly.com/gochi...-week-two.html shows image examples matching an old Calpis advertisement and comparing to the one used in the show. Clever way to get around royalties, thanks for showing that.
Oh, and I think it makes more sense to leave "Gochisou" alone as it doesn't really have a direct translation, or one that really makes sense in English. I think the explanations provided here would suffice, but that's up to admins.