Beetlejuice: ESTP -- Seems pretty clear, yeah.
Lydia: INFP -- Seems a little cliche, but probably best bet.
Delia: ESFJ -- Fits her, good call.
Otho: ENTJ -- Wasn't sure at first, but that sounds good. Picking up the Handbook without telling anyone, then pulling it out as a trump card when everything depended on it. In other words, good scheming skills.
Disagree with:
Charles: ISFJ? I see Introvert, Si, and perhaps Fe. Good at navigating uncomfortable social situations, but sure likes his privacy and stability.
Adam and Barbara...not sure about them, really.