Lori Beth seemed to be around more than she had been, lol! They did kind of use her to keep Richie's spirit on the show.
Potsie too, he didn't have any of his friends left. They did work him into some episodes, but it still felt kinda weird. i think they wanted to have some old characters around, even if just in the background, while the new ones were introduced, to keep the show feeling familar.
BTW--did Potsie EVER graduate college?