I really like the idea! Great job. And I'd love it if someone were to actually do this (I won't at this point since I'm already busy with other mods, see below for more).
Some thoughts: Why not just use the Ebon Hawk for the player? I know you wrote that it's because the EH is not allowed on Telos but I doubt anyone would care at this point and it's always nicer to use your own ship instead of a generic shuttle.
I love the part where Bao-dur sacrifices himself to destroy the Ravager. That's always what I had in mind when it comes to his fate. One thing I'd add here is the option to leave the Ravager intact and falling into Citadel station as seen in a cut cutscene. That could be a dark side choice that Bao-dur supports if he himself is DS as well (no idea what to do with him in that case), or if he's not dark sided, the player could try to persuade him but he refuses to leave the Citadel station to die and so the player either has to kill Bao-dur himself or Bao-dur stays and blows up the Ravager.
And maybe the gameplay could be streamlined a little bit as the endgame already consists of many random battle encounters and your idea seems to add even more. The merc camp for example is a nice idea but could maybe work as a puzzle instead to change up the gameplay some more. Also having Mandalore face Nihilus alone seems not really important, so maybe he and the Exile could regroup earlier. One possibility would be that once Mandalore gets to the locked elevator, the game cuts back to the Exiles part, which is taking place at the same time and then the Exile and Mandalore meet shortly afterwards.
As I am/was part of that mod team, I'm afraid you're correct. This mod really is dead or at least very close to it. Or to be more precise, it never really lived at all. This is due to bad communication among our small group (which at least partially is also my fault) and now Cirosan seems to have left this site, Fair Strides seems to be busy with other projects / real-life as well and the same holds true for me.
And to be honest: I prefer your story outline for Bao-dur's sacrifice