In Emiya-san Chi no Kyou no Gohan, we are presented with a timeline akin to Fate/Hollow Ataraxia that the servants of the Fifth Holy Grail War live peacefully with their masters. However, at least for the anime adaptation, there are hints that the Fourth War had occurred in this timeline:
Kiritsugu appeared in Shirou's flashback and had remarked that he missed eating hamburgers back in Germany.
Irisivel has yet to appear and Illyasivel lives in the Einzbern castle. Other parental figures from the Fourth War are also absent.
Those hints does not contradict what we know in Fate/Zero. So what happened to the participants of the Fourth War in this timeline?