Boba Fett....that's a tough one. I think if we can do more things with him and his death, we should. If we can't, at least have Han PURPOSELY hit him into the Sarlaac. But I'm really against his non-inclusion.
And Lando needs to live. Lando dying wouldn't be tragic so much as it would be anti-climactic. Plus the Falcon flying away from the exploding Death Star is one of the most iconic scenes in ROTJ.
Anyways, that's just my opinion.
I'd be interested in seeing Han purposefully knock a dazed Boba Fett off of the skiff. Maybe someone could at least demo it to make sure flows decently.
And Lando dying would only be a change for the sake of making a change. While the earlier foreboding of Han worrying that he wouldn't see the Falcon again may open the door for Lando becoming space-bacon, the scene works just as well for a future scene of Han dying, rather than Lando. But because such a scene exists, doesn't make it a requirement for either one to die.
It is too bad we don't have footage of Han reassuring Leia that Luke made it out alive and then Leia mockingly reassuring Han that the Falcon made it out alive as well.