Oops minor modification for me. Here's how I personally like to read the stories:
1. http://www.mangago.zone/read-manga/sabita_yoru_demo_koi_wa_sasayaku/
2. http://www.mangago.zone/read-manga/hadakeru_kaibutsu/
3. http://www.mangago.zone/read-manga/azami/
4. http://www.mangago.zone/read-manga/renai_rubi_no_tadashii_furikata/
Oh? So you would leave renai for last? I mean, i agree that azami can be read whenever, it's a little background to Kan-chan as you very well said, but it just doesn't make sense for me to read renai last, especially because that is where Kan and Shuuna's relationship starts, like, their fist moments together and a lot of hardships they had to overcome. I especially believe that the photo subject in hadakeru, right at the start, holds more meaning if you read renai first.
Also, for hadakeru you will need to read the raws of the last 3 chapters ( at least i haven't found it translated anywhere T.T ). Again, this is what i personally believe, and i would love to hear from you why that particular order (๑❛ᴗ❛๑)
I've read all of their stories and even when I 1st read Sabita, there was always about Kan-chan's charactet that bothered me. I knew there was more to his character that psuhed him to the dark side. Urgh! Those damn colleagues of his.