Maya and Amelia's friendship, along with Peter Scott and Peter Almsley's
Amelia's utterly sweet romance with an injured patient
The Gates of Sleep
Marina being able to see through her aunt's half-lies about her mother to realize that her parents didn't abandon her at all and her mother suffered horribly not being able to see her. Her realization is later supported when she is thrown into a pocket dimension because of the curse and meets the ghosts of her parents.
At Marina's wedding, when she is almost down the aisle, she sees the ghosts of her parents hovering above the altar, smiling at her. They then throw "rice" in the form of flickering lights that hover over and slip into the hearts of everyone there, with the two largest lights settling on Marina and Dr. Pike.
The Wizard of London
Sarah befriending Nan.
After making social calls to gather magical allies and bracing herself for chilly reception, Isabelle returns home with the realization that some of her best friends from school had never abandoned her and still cared deeply for her. One of them refused to let a stuffy butler shoo Isabelle away and swooped down from the second floor while still in her dressing gown to get her!
During Alderscroft's moment of darkestdespair, Sarah steps towards him and offers to be his friend.
Phoenix and Ashes
Reginald has a PTSD triggered Freak-Out that results in him trembling in a corner of his bedroom. After having very little in the way of psychological support (sadly, Truth in Television given the time period of the story), he then receives a visitor in the form of his godmother, who coaxes him from his hiding place and just listens to him, not judging him.
Home From The Sea
Nan and Sara are now in their twenties and Alderscroft treats them better than he would have treated his daughters, including finding good work for them, making sure they are comfortable, and inquiring after their well-being.
The gate to Heaven opening for the ghost children, and them happily running through it.
The Selch greeting Mari as their own.
Mari taking on seal form without a skin to find her children amongst thousands of seals, since a mother seal would be able to pick out her own.
The very end: Jack Prescott at home, nervous and fretting... and gets up to welcome Kate home.