Hmm. Just saw a brief glimmer of hope, only to be dashed cruelly once again. The second code, written on the kana keyboard is as follows:
B51BIQPGS206HD
こえぬこにたせきとふわおくし
If we write that first こ as a ご instead, and then take the first romaji letter of each kana, it starts “genk” - and we were thinking maybe this code corresponds to “genki-textbook”. 
Except after that it turns into noise - “genkntskufwoks”. And none of the other codes work even that well. 