Plot hole: Jane badly wants to sell the Maitland home, so it's not practical that she left all of their furniture, decorations, and other possessions after they died. Any realtor who wanted to make a quick sale would have the place cleaned out, instead of leaving so much stuff for the new owners to deal with.
Suggested correction: Actually, it's not all that uncommon for realtors to sell fully furnished and "staged" homes. And depending on the location and market, they sometimes sell quicker than unfurnished homes, since it means that it's less for the new buyers to purchase. This especially makes sense, since Jane seems to like the idea of selling the house to a larger family who might desire such things. As for their possessions? There was probably no family who wanted them, and Jane probably just hadn't gotten around to getting rid of them yet, since the Deetz family seems to move in rather quickly after the Maitlands died. I feel like at best this is a "stupidity" or "character mistake", but I'd argue it's neither.
Suggested correction: Jane tells Lydia that she "personally decorated that house," so it's not impossible that she was maybe looking to be hired as the new decorator.
I always thought Jane was lying when she said that she decorated the house. The Maitlands were quite offended when the Deetzes began to change everything, as if they decorated the place themselves, and chose/inherited the furniture. I think Jane was nosey and wanted to keep getting attention for herself. But this is just how I interpret it.
Other mistake: Adam adds a funeral scene to the model of the town. There are two wreaths with his and Barbara's names. However, they can't leave the house. No way did he go to a store and buy those.
