...when she disappeared from the series? How about the Laurenzos, who were the friendly neighbors once the Jeffersons moved?

...when she disappeared from the series? How about the Laurenzos, who were the friendly neighbors once the Jeffersons moved?
Yes the Laurenzo's just vanished. First the husband went poof and then when the actress got a Laverne and Shirley gig she was gone too.
Its funny because the actor Vincent Gardenia who played Frank Larurenzo played Jim Bowman who sold his house to the Jeffersons. He appears again in the Meet the Swingers episode before becoming Frank Laurenzo later on. He left because supposedly he was irritated on how his character had to wait around all day to be filmed. He was not happy with how the show was filmed.
He also played a judge on Maude. He was nominated for an Oscar around the time he was on the show which could explain his attitude at the time. He was nominated for another Oscar many years later for Moonstruck. Brilliant actor but I've read his attitude was not great on All In The Family.

If I remember correctly, in the episode where Teresa moved in she mentioned that she would only need the room for a month while she was taking her Nursing boards. Which didn't seem to make much sense why she needed a place just for the time she was taking her exams. Where was she living BEFORE and where was she going to live AFTER? Alas, we will never know.

As for the Lorenzo's...like Chuck Cunningham; one day they were going never to be seen or heard from again.

The Lorenzos probably left about the time Betty Garrett got the Laverne and Shirley role.