False. If Riki and Rin don’t remember anything expect Refrain, then all of Rin’s portion of Refrain is senseless. In Refrain Rin remembers all of the friends she has made and the time she spent with them.
Riki remembers playing baseball with everyone, so he definitely remembers the events of the common route. As for the routes, Riki is unaware of Kud’s hometown, and doesn’t remember anything about Yuiko, so we can infer that he doesn’t remember the heroine routes…
All of the heroines react to what happened.
Haruka:
Mio:
Kud:
Yuiko:
Komari and Rin:
However, if we go by the time-line of the Yuiko true end, Riki should remember the events of the heroine routes at the start of Fall.
