I'm kind of interested in Viera's skill. If I do ever level/SAW her, I'd use her as a Valk/Pegasus friend for UP generation, as well as a gold get friend to squeeze more gold out of non-Pastoral Gate maps when I can.
So far, I've gotten Hana to 4/5 -4, Marie 4/5 -4, and haven't started on Beatrica yet, but probably won't spend SC or anything to mincost her. Also mincost'd Mischa since she was dropping so much from the Hana map.