Allie's! Allura would have gone because she is all about new experiences. She wouldn't know any of the songs, but she'd gladly cheer everyone on!
Daisy went and would've sang after having a few drinks. She's not super horrible, and she would have sang Hit Me With Your Best Shot.
Dinah would have sang quite a few songs, and done duets with anyone who wanted to. She hasn't really enjoyed herself singing this much in a long time. She'd sing Barracuda, I Wanna Dance With Somebody, and I Put A Spell On You.
Hilda went to support Lucifer and Sabrina. She could maybe be coaxed into singing.
Ochaco would have gone with Sabrina. She sang Love Story because it's cute and upbeat. She'd be up for singing with friends, too.