“Cut all Enterprise B scenes”
Reading through this, I don’t really understand this decision. It sounds as if Kirk will just show up at the end with insufficient set-up. And it also sounds like this episode doesn’t really have an opening (the boat scene feels like a post-credits opening; I don’t remember TNG having pre-credits openings which were character based rather than plot setup very often). I would try cutting together the Enterprise B stuff into a teaser; you can quickly set up Guinan and Soran that way, and then end it on Captain Kirk “dying”, and then roll opening credits.
I kind of feel like if “Insurrection” was actually a TNG episode, the Riker/Troi stuff would be a major B-plot and it could easily lead directly into the wedding, rather than saving that for “Nemesis” where it has nothing to do with anything going on. The show never would’ve had every character have things happen in the same episode, and Nemesis already has a major plotline for both Picard and Data, it doesn’t need a wedding too. You could do a thing early on where Picard tries to get through to Data by asking about the song and it doesn’t really work and then at the end Data is singing a song at the wedding, so it feels like some kind of pay-off rather than a random gag (which, admittedly, it makes me laugh, but I acknowledge that it’s character breaking and dumb).
Just my two cents, I’m sure that you have thought these things through and have reasons for the decisions you’ve made.