If Cbob is completely out of the picture like that, then why shouldn't Marty go ahead and update the epilogue scope? I'm not saying this as a "f*** you" to cbob, but if he is indeed completely out of the picture, then it would stand to reason that all creative control he had over the product has been given up. That's not to say that Marty should completely rewrite the epilogue, but I wouldn't see adding additional content to the epilogue as disrespectful to cbob either. If anything, it would be honoring cbob while improving on the product. But, in the end, this is Marty's game. It is ultimately his decision on what to do. If it were up to me, I would say increase the scope of the epilogue just a little. At least enough to do one last sex-a-thon through all the characters MC met throughout the previous books and tie up all the hanging plot threads. Or maybe a happy ending.
Long story short, if the only/main reason Marty is on the fence about increasing the scope of the epilogue is because that's the plot cbob wrote up all those years ago, then I would say "add a little bit extra." If the main reason he's undecided is because he truly believes that everything gets wrapped up with the current version of the epilogue, then don't bother "improving" the epilogue; it's fine the way it is.
Long story short, if the only/main reason Marty is on the fence about increasing the scope of the epilogue is because that's the plot cbob wrote up all those years ago, then I would say "add a little bit extra." If the main reason he's undecided is because he truly believes that everything gets wrapped up with the current version of the epilogue, then don't bother "improving" the epilogue; it's fine the way it is.