Given this, I think most of the objects in the galaxy would remain gravitationally bound to each-other as a galaxy.
I don't, not indefinitely anyway. I just imagine that it will take a very long time for the galaxy to fall apart. But ultimately, I would have thought that SMBH's play a critical role in holding together their respective galaxies. That's a serious distortion of spacetime, even if it is a mere fraction of the overall galaxy mass. It's certainly going to influence anything close to it, which in turn influences anything close to that... the drift will be contagious. 4 millionths of the mass of the galaxy? Yeah, a very long time indeed. But it'll fall apart imo.

Bravo on the haiku.