why not have a karaoke machine, invite them to sleep over and let them party at home? if not you can look into renting out a bar or something but that seems a bit much for 12 years old.
when i was 12 (and 24 and 30

) i wanted a dance party too, so we (all those years) invited my friends, had goodies to eat and drink and turned my living room into a dance floor. she'd probably have a blast doing that, if i know typical 12 year olds.
have fun!