Him being digested would be a great framing device. Film starts with being slowly digested, Fett is disgusted by his failure on Jabbas barge and has given up on survival. Cue LOST style flashback to Fett as a wimpy kid whose dad was killed by Nick Fury but through the rest of the flashback becomes a bad ass and the best bounty in the galaxy. Films ends with Fett realizing the flashback is induced by the gas within the Sarlacc Pit as way to distract its prey while being digested. But by being made to think about his past the Sarlacc has inadvertently reinvigorated Fetts determination and he claws his way out with one thing on his mind: REVENGE.
It writes itself!
It writes itself!