JUNE HAVER... the sweetheart of so many musicals at 20th Century-Fox and Warner Brothers, was regularly described in studio press releases as 'peppy'.  She is still peppy and that description, as well as her ability to sing and dance, is what made those wonderful film musicals endearing as well as 'peppy'.      June was brought to Fox to be the successor or rival or perhaps 'clone' for their reigning queen,  BETTY GRABLE.  In the mid-1940's she made a bunch of sprightly musicals and even co-starred with BETTY in The Dolly Sisters.       In the early '50s she went across Mulholland to the valley to star in several Warners musicals.  The most memorable was Look For The Silver Lining with RAY BOLGER in which she portrayed the famous Broadway dancing star, MARILYN MILLER.      In one of her films, Where Do We Go From Here?, she met FRED MacMURRAY.  They immediately took a shine to each other and were married in 1953.  It was a happy and long relationship, lasting until FRED'S death in 1991.  In 1966 they adopted twin girls, Laurie and Kate.   Today, Laurie owns an advertising agency and Kate is a screenwriter.      June tells us that her first screen appearance was a very small bit in the ALICE FAYE/CARMEN MIRANDA musical, The Gangs All Here.  After that, she says, Fox kept her busy doing screen tests with budding studio newcomers.