haha, I can relate!
In 2010ish we planned for the last 4 p.m. meet and greet for Snow White in Epcot - then she wasn't there. Our then 4-year-old complained about it constantly over the next year. It felt like every.single.day. LOL
On our trip almost a year later she was wearing her Snow White dress when we entered MK on our 1st day and a CM immediately pulled us aside once we tapped in and immediately steered us to Snow White where he said it was a "secret" spot and no one was on the line. He had NO idea how much we appreciated that after the last year
Sorry for too long OT...
But as for the party, we've only been to one in August 2019 - the second party. Super crowded that year. We missed 7 Dwarves in 2019 by minutes as I think they ended at 11 and we were waiting until later for lower lines since Stitch earlier was at least 2 hours (DH and I left our old-enough kids to go do other stuff!) and waiting in a second long line was just too much party time lost.
Edited to add: So I guess some character lines end early? Was that the norm that year? Since it was our first MNSSHP we assumed everything went until midnight.