Muffin But Murder question

Our story begins with our heroine, Merry Wynter -yes Merry Winter ;-)- having inherited a castle in upstate New York from her great-uncle. Recently unemployed Merry can not afford to keep the castle and along with her friends and housemates Shiloh and Pish decides to throw a Halloween party to showcase the castle and property in hopes of interesting a buyer. Along the way, Merry encounters her fair share of strange people; some of whom actually want her to leave. When her property is vandalized it seems the sheriff is powerless to do anything. Merry goes ahead with her party and despite the presence of some uninvited unidentified guests and the fact that some names on the guest list are checked off twice, all goes smoothly...until Merry is straightening up aftewards. It is then she discovers a real dead body in the coffin she had used as a decoration.
Who's body has she discovered? Why was he at the party and more importantly why was he murdered? Is there any significance to the fact that some guest names were checked off twice on the invitee list? What if any significance does the bank problem have to what is going on? And what do we think about Cranston Higgins - legitimate heir or scam artist?
I must say there are a lot of throwback references to characters from the first book, some of which I find confusing.