Okay, a little confused on which girls pop up more in silver gacha and thus are more replaceable.
Earlier, you said "story" girls pop up more frequently- I looked at the current silver contents, and tried to pick out the "story" girls - Elena, Adelitte, lillium, Bridgette, and Lisette? or is it just any girl that only needs 1 random girl instead of 2 random girls to promote to SR?