I've read through these, but, if I'm not mistaken, these seem to be the same endings we have available now:
she either dies, she goes to Avernus, or she turns into a mind flayer. The main additions I see is that Withers leads the party into an epilogue during which their fates and choices are discussed, but I'm not seeing anything different about the actual ending choices...
Maybe I'm not finding the new stuff?

Justice for Karlach