Oh wait. I think I'm looking at this wrong. Those instruments are not missing. Actually, I think those are just track names, not the actual VI names. It's an FX plug-in called "TH2 SONAR" that's missing. Those just happen to be the two tracks which have that plug-in assigned as a FX. I guess I should have shared more detail about the error message. The missing plug-in list actually read:
TH2 SONAR (Track: 'Soft Rhodes')
TH2 SONAR (Track: 'Dirty Wurli')
As I said, I have not installed Melodyne, Rapture, Addictive Drums and D-Pro yet. But I'd really be surprised if that plug-in is supplied by any of those.