This may not be your kind of "FINALLY!" but it's certainly mine:
Backstory: Phoebe is 14 years old and I got her as a kitten. Mandy came into the picture at age 3, when Phoebe was 6. Phoebe lived upstairs for almost a whole year after Mandy came, only coming downstairs in the middle of the night or when Mandy was in her crate. I always wanted them to be buddies and see Phoebe curled up with Mandy. Ha! She has only slowly come to "accept" Mandy and will even walk under her legs and let Mandy sniff her, but only a little. This was big progress!
And speaking of the chimney, here is a progress pic: