any version of the game had their faces but not names, that's why it had been argued why they didn't have a name while minor roles had their own name as unexpectedly Setsuna's mother is one of the famous character among fans
I think Maruto had thought some of the name based on what I heard in radio and he wanted to make it similar to Setsuna (雪菜）but well the winter (冬) had been taken by Touma (冬馬) so he went with Akina (秋菜), if only there's a natsu too as haru has already been taken by Haruki (春希）