I stumbled upon a website with scanlated pages of Mizu To Gin, the prequel of Natsu no Zenjitsu. I saw the older versions of Tetsuo and Hanami there. I have yet to finish the 65 pages of the first chapter but one page suggests that Hanami dated Mori, Tetsuo's friend from his band.
Thoughts? I'm relieved that Tetsuo and Hanami are just friends... well, the next pages may suggest a development in their relationship so I can't assume pure friendship.
I also wonder how Tetsuo ended up wanting to teach art. I hope much will be revealed here in NNZ.