But the credits for ep. 18 and 17 list two different actresses for each role. Cora will be played by Barbara Hershey and the Queen of Hearts was played by Jennifer Koening. That means Cora, Regina’s mom, is not the QoH. If the producers had wanted to make Cora the QoH, all they’d have to do is hire one actress (Barbara Hershey) and cover her face until the big reveal. It’s much more affordable to hire one actress to play two parts than to hire two different actresses to play one part. The reason they kept the QoH face covered is for an unrelated reason such as disfigurement.
Two different characters, two different actresses.
1. The Queen of Hearts is played by Jennifer Koenig
2. Cora, Regina’s mother, is played by Barbara Hershey. 
"That’s how you know you’ve really got a home. When you leave it, there’s this feeling that you can’t shake. You just miss it." Neal Cassidy