Complex sentence: This would be the last special to star Billie Mae Richards and Jackie Vernon as the voices of Rudolph and Frosty respectively, as well as Mickey Rooney as the voice of Santa until 2008's "A Miser Brothers' Christmas".
Split into simpler sentences: This would be the last special to have Billie Mae Richards and Jackie Vernon as the voices of Rudolph and Frosty respectively. It would also be the last special to have Mickey Rooney as the voice of Santa until 2008's "A Miser Brothers' Christmas".