I don't like making super long TL notes, so I'll just put this here instead.
For those unaware, Japanese people really like wordplay and this is especially true with numbers and dates. Anyone that looks at a lot of Japanese fanart has probably noticed that you get a lot of "Nice X Day" entries during November. This is because the Japanese word for "nice"/"good", "いい", looks like 11, so it's just a matter of making another pun off the number of the day (thus 8, which looks like a pair of boobs, becoming "Nice Boobs Day", etc.).
Here, the numbers 1 and 6 have possible readings with "hi" and "ro", respectively, so they can be read as "Hiro". Thus, November 16th is "Nice Hiro Day".
The Hakata-go ("Kokura-go" in this drawing in reference to DreJour winning the Kokura Daishoten) is pretty much a running gag in Doudeshou with how grueling the 12 hour or so journey was for the cast and crew.
