Who Benefits From a Rocket Primary?

Summary

The implosion of scandal-ridden U.S. Senate candidate Graham Platner's campaign in Maine and the sudden passing of U.S. Sen. Lindsey Graham in South Carolina give a fresh pack of candidates a chance to make history. With Maine's Democratic Party having until July 27 to name a new nominee, and a fast-tracked special Republican primary in South Carolina set for August 11, who stands to gain from an unexpected and condensed primary season?