What if Harrison Declined to do the third film?

They could have had him die in the carbonite.

Harrison gets his wish that the character is dead. But fans everywhere would have been devasted which Lucas knew. He knows kids don't want to see the hero die.

Also in the movie serials he was emulating the hero could die one week at the end of a cliffhanger and come back the next week without a scratch.

What if it was Han who flew the falcon into the second death star and died trying to escape the fireball that lando somehow survives going yeehaw!.

You see Lucas could not win. If he killed Lando he would be racist. If he killed Han Solo the parents of children would write to him angry just like if he had luke or leia killed. The kids would no longer buy the action figures or the comics or novels and tie in merchandise.