Based on my experience, this mod works as advertised, but has some issues. Specifically, I sided with Vaklu on Onderon with the goal of sparing Kavar to avoid the Dark Side path at the enclave. The first thing I noticed was the dialogue option to simply skip his fight, which entails telling him "Wait! there's another way! Get your shit and get the fuck out of here!" I find the choice of words immersion-breaking to say the least. (I also feel that an easy skip option is rather cheap, but that's a me problem.) I feel silly for not thinking that it could be a test option.
The post-fight dialogue convincing him to surrender is very well-written, but a bit wordy. I think it would be more impactful if Persuade checks were required. I was able to spare him with no chance of failure short of a misclick, so it wasn't as satisfying as it could have been. After further study, I now see that this dialogue tree is far more complex than I initially realized. I did find a path that got Kavar to stand down on my first try, but there are many more where he sadly just can't compromise, even though your arguments are equally nuanced and logical. It's genuinely tense. Fine work.
Lastly, the Lost Jedi quest does not update if Kavar is spared this way, and the Master of the Palace quest states that he is dead. Kreia's dialogue also does not update like it normally does. Kavar still appears at the enclave, however, and the scene proceeds as if nothing on Onderon happened.
This mod is one I have wanted for a while since Kreia's endgame dialogue implies that Vaklu actually is better in the long run. It has a couple kinks to iron out, but I'm very glad it finally exists.
I believe there's some discussion of it in this thread. Physically adding additional room models is pretty trivial. It's mostly a question of what you do to flesh them out with actual content.