And just to address some unanswered questions for future readers of this thread:
A reason you don't see some of these suggestions in furniture/cabinetmaking is the word "telegraphing". You learn to not penetrate any surface if it will be either veneered or paint/lacquered. There is always a good chance that any surface imperfection/repair will eventually show up in the finished surface.
Depending on where your bracing is, and how it's positioned, there is always (gasp!) construction adhesive. It's thick, gap filling, and slow to set up, but sets hard. Only to be used when hidden on the inside, of course.
