If you ever do another Kiss cover, do one of their early ones like Black Diamond, Deuce, Strutter or 100,000 Years.
I think you'd do well with Amy Lee/Evanescence "Bring Me To Life" and "Call Me When You're Sober".
Have you tried Janis Joplin yet? "Piece of My Heart" you'd slay with your vocals, but there's not a lot for instrumentation, so you could give it a new hardness. Update "funny, just found your YouTube video for this, awesome".
I like your originals too.
Love your videos, love the metal most, do some more Black Sabbath, Iron Maiden, Metallica.
I'm not a big female vocals fan, but there's just something captivating about Melody, I really enjoy her voice and range. You're all fun to watch. Abigail looks like she's having so much fun, show more of her.