Not to mention at some point everyone had their own bathroom, although they also had shared bathrooms. And the garage apparently was entered through some dimensional gate, because otherwise it would be in their bedrooms.
My favorite continuity issues are the children of Rose and Blanche. I guess it's not so much continuity as it is just amazing that they both had at least 5 kids: Rose had Adam, Ginella, Kirsten, Bridget and Charlie and Blanche had Janet, Rebecca, Biff, Skippy, Matthew and Doug. Blanche especially since she wasn't a big fan of kids. And having them all raised in that house...oh wait, maybe they weren't cause Rebecca didn't recognize it...here comes the headache!