I just finished reading volumes 16 and 17 of Megami no Café Terrace. The series continues with light romantic developments (mostly around Akane and Riho) and quite a bit of world-building regarding the backstory, all while developing the current heroines a bit more.

In these volumes, we got some development for Ami through a small side story revolving around her childhood friend. The friend stayed at the shop for a few days while preparing to propose to her current boyfriend. During this time, the interactions with Ami gave us a nice glimpse into their past together.

They even hinted at Ami leaving to take care of the grandmother after her childhood friend would marry, but everything gets solved without any change in the status quo much like what happened to Ouka in the volume that had her leaving for France. 

There was some small development for Akane too, as she was left alone with Hayato for a day. That allowed them to develop their relationship a little bit. Nothing extreme though, just your usual fanservice scene followed by the inevitable "tribunal" once they got discovered before anything important actually happened.

There are also some more flashbacks about what happened to Hayato's grandparents after the café burned down. Honestly, there weren't any huge surprises there. It was just some additional context about their life together afterward, but still no real hints about what led to the café being rebuilt.

Fuwa seems to be still plotting something. He tried to open a rival shop to steal customers, but so far everything has been thwarted for one reason or another. The issue is, will this lead him to become more radical? Is he going to try and bring the entire establishment down using less legal methods?

Now, the next volume seems to be about Ouka's little sister, Kikka, targeting Hayato in a romantic way. I am sure it will just be a single-volume thing as it is quite late to add anyone new to the main cast, but it will be interesting to see what kind of reactions it triggers in Ouka.

She has been mostly passive in the race to get Hayato's heart (at least compared to Akane and the others), so we need to see what happens once she gets serious. Will she inevitably be the one winning the race due to her looking like the "main heroine"?