I was of opinion partymum & birthday girl had been unfair. The sleeping arrangements excluded her.
OP's updates slightly change context, as they are sneery.
Most 11+ y.o.s want to be left to their own devices with their friends for sleepovers, the foods sounds lovely too. I arrange activities for DDs' sleepovers (crafts/ make up session, new film) for that age but mostly found they want to natter under a duvet fort, watch You Tube together & invent their own games!! My 10 y.o. and her friends made a comic book together based on You Tube characters at last sleepover, totally their idea.
This may or may not be the casewith OP's DD, (but the updates kinda indicate it's possible), on occasion there's a child invited that turns out to be 'mardychild' & moans about everything/ won't join in. The one you offer to ring parents for/ or take them home 'as they seem unhappy /they're not enjoying it ' but they don't want to go home.
So when asking DD about what happened, I'd be mindful of checking whether she was moany. There might be more to dynamics. Either way, DD should have asked to ring you, to take her home.