The front of the Stivic's house shown which was the same house that the Jeffersons lived in bares no resemblance at all to when it was first shown in "Lionel Moves Into The Neighborhood."
When Archie calls and speaks to Edith he is so drunk that he doesn't even remember who Gloria is. If he was so drunk as to forget his own daughter he would not have the presence of mind to call Mike & Gloria's phone rather than his own home number to speak with Edith.
Mike is doing all the maintenance work around the house, because he says he can't afford to hire anyone. Since the Stivics are only renting the house from the Jeffersons, George Jefferson, their landlord, should be responsible for all the maintenance work on the house. (Note: George may have arranged to reimburse Mike for any minor repairs, but Mike doesn't have the money to start with).
Mike says he successfully fixed the front door lock just before Archie makes his first appearance. After Archie leaves for his convention, however, Mike says he'll get back to the lock later.