Thanks to Ranmen11 for the suggestion.
Lydia
With Adam and Barbara
Oftentimes will go upstairs to the attic at night when she can't sleep or has a nightmare or just feels the need to talk to the Maitlands. She's done it so much that both ghosts find it a whole lot easier to tell if something's wrong.
Goes to the Maitlands for support when something she's unsure she should talk to her living parent or stepparent about starts bothering her.
Definitely has convinced Adam and Barbara to mess around with her via her ouija board more than once. Things that she has managed to get them to do range from spelling out any random word that they can think of to changing their names to something completely random that Lydia herself finds incredibly hilarious.
Sometimes will ask Adam and Barbara to do something funny with the house's electricity just to prank her dad and Delia.
With her dad and Delia
Goes to either her dad or Delia whenever she has an issue of which the Maitlands can't help her out with.
With Delia
It's rare, but Lydia will sometimes go to Delia with some sort of emotional issue that she needs help with.
With her dad
If Lydia wants to talk to her mom, her father takes some time out of his day just to take his daughter to visit her mother's/his first wife's grave.
Adam
With Lydia
Like Barbara, Adam can often sense if Lydia's in distress and in need of them. Is unsure of whether it has to do with the fact that he's kind of like a ghostly father figure to the teenager or if it's more or less got to do with Lydia's medium side.
With Charles and Delia
Alongside Barbara, he once took part in an adult-only meditation session with Charles and Delia.
With Charles
His 'which of us is more fatherly towards Lydia' competitions with Charles are often done for laughs and are fun. Often wins, but lets Charles win these a few times just because the latter is Lydia's real dad.
With Delia
Finds meditating with the living woman kinda relaxing. As with the therapy sessions that they both, Barbara, Charles, and Lydia do.
Barbara
With Lydia
Like Adam, Barbara can often sense if Lydia's in distress and in need of them. Is unsure of whether it has to do with the fact that she's kind of like a ghostly mother figure to the teenager or if it's more or less got to do with Lydia's medium side.
With Charles and Delia
Alongside Adam, she once took part in an adult-only meditation session with Charles and Delia.
With Charles
Doesn't interact with him much, but the two have become really good friends.
With Delia
Once had a female only therapy session with her and with Lydia.
Charles
With Adam and Barbara
Is actually happy that the Maitlands sometimes step in to help him and Delia with parenting Lydia.
The three of them will often lament together about dealing with loss.
With Adam
The two men will often pit against one another in determining who's more fatherly towards Lydia. Charles is jealous when Adam keeps winning. Though they just do this sort of thing for fun and for a laugh.
With Barbara
Doesn't interact with her much, save for when Barbara comes to tell him that Lydia wants to talk to him.
Delia
With Lydia
Is still kinda sorta Lydia's life coach. But she also doubles as a therapist for Lydia.
Sometimes will try and get Lydia to meditate with her, but the younger goth teenager will often refuse. Once successfully gets her to meditate once she tells her that the Maitlands agreed to meditate too.
With Adam and Barbara
Often meditates with them.
Acts as a sort of therapist/afterlife coach to the Maitlands (who don't seem to mind although they do find the term 'Afterlife Coach' to be relatively funny).
As a family
Will do family therapy sessions together from time to time. Oftentimes, these end with the five of them doing something they find fun and is completely random (this ranges from a pillow fight that ended with the entire living room covered in pillows after Adam and Barbara used their powers to summon way too many to the Deetzes ending up falling asleep in the living room after one of their therapy sessions went on way too long (the Maitlands did not want to disturb their living housemates and retreated to the attic)).
They do family game nights once a month and horror movie nights (Lydia's idea) twice a month.
A/N: Feel free to put suggestions for headcanons in the comments.
