It would be nice if they finally added a friendship meter for Merula. But for the sake of story consistency (however bad Jam City is at it), it shouldn't be unlockable until you reach Beyond V1.
i mean they made her weird version of draco but to me she was interesting design+possible lore for her until they made her inconsistent which is why i have my MC date her cause this way her behavior is just cover for not exposing our relationship xD