Revealing mistake: When Dorothy and Blanche are in Rose's room, look at Baby. Its very obvious its just a stuffed toy pig. You can tell by the fluffy skin, the unnatural ear movement, and the covers would be moving up and down as its breathing. You can really tell its fake when Rose gets up off her bed. (01:08:45 - 01:10:25)
Continuity mistake: In this episode Blanche says she has had 4 children, but she has never owned a Mercedes. She offers one of her three sons (named Biff, Doug and Skippy) to Dorothy in order to let her keep the car. In other episodes she mentions daughters Rebecca and Janet frequently, and in the "To Catch a Neighbor" episode she mentions a son, Matthew, who is a CPA. That's at least six children by my count.
Answer: Ice makers were a new invention, advertisement purposes.