After she failed to resurrect Leota, I don't think the latter was present at the casting or in Hyperion Heights.
Lady Rapunzel wrote:
"Hey Mr. Owl, how many members oif the coven will we actually get names for?"
"Let's find out...1, 2, 3..." The world may never know.
I'm really disappointed that they built the coven up. Do I remember correctly that we were told season 7b would get an episode revolving around each member's background?
Nah, they never said that.
Kitsis did say, however, "We'll definitely recognize a few of their names, absolutely. These are witches from iconic fairytales or Disney lore." And that turned out to be true only of Leota and the Blind Witch.
It seems that aside from Seraphina, the rest were "supporting character" hedge witches like Sage.