Linda Ellerbee, doing a waxing-nostalgic series on the halcyon summer of 1967 for ABC's "Good Morning America" this week, was asked to bring in experts to ruminate on the cosmic meaning of the Summer of Love. By way of reply, Ellerbee said, this morning's closing chapter will offer direct descendants of that era: Mary Travers' daughter, Elisha; Ken Kesey's daughter, Shannon; Michelle and John Phillips' daughter, Chynna; Dexter King, son of the late Rev. Martin Luther King Jr.; Abe Guthrie, son of Arlo, and Santita Jackson, daughter of the Rev. Jesse Jackson. Vanessa Veselka, 18, also will be there. Veselka frequently comments on "life its ownself" and the antics of her mother--a lady by the name of Linda Ellerbee.