Miina Tominaga（冨永みーな）has been a name that I have seen and a voice that I have heard on Japanese TV as a narrator, but not a seiyuu that I have ever come across in anime all that often unfortunately. I've read that she played the third Katsuo Isono（磯野カツオ）, the sometimes naughty brother and son in "Sazae-san"（サザエさん）and another role in "Sore Ike! Anpanman"（それいけ!アンパンマン）, but my only hearing of her in an anime during my visits to my anime buddy's house thus far has been as her villainous role of Majorina（マジョリーナ）in "Smile Precure!"（スマイルプリキュア!）back in 2012.
According to her resume, though, Tominaga has also been a singer and in September 1985, she released an album "M Marble"（Mマーブル）. From this album, I bring you "Hito Natsu no Memory" (A Memory One Summer), and it sounds like a jazzy love ballad filtered through cute synthpop although I couldn't track down who was responsible for words and music (Ahh...did find out; Satoko Shimonari（下成佐登子）took care of both words and music). Plus, Tominaga, who was probably around 19 at the time, sounds more like a lovelorn Precure here than a cackling witch. I would be curious in finding more about her discography in "M Marble" as well as for any other releases by her.
She was born Yoshiko Tominaga（冨永美子）in Hiroshima Prefecture in 1966. From what I read in her J-Wiki profile, when she was in elementary school and already a child actress, a fortune teller gave her advice to the extent that she changed her stage name into Miina Tominaga with the first name in katakana（冨永ミーナ）before it was further switched into its current hiragana form. For further trivia, her sempai at the Nihon University College of Art were Hikari Ohta（太田光）and Yuuji Tanaka（田中裕二）, the famous comedy duo Bakusho Mondai（爆笑問題）.