re: How do bands usually divvy up money between members?

For every record/CD sold, the label gets a cut, the performer gets a cut, the writer gets a cut, and there's probably a few more that I don't know about. So the members of the band would split the 'performer' cut, while whichever members wrote the songs would split that portion. Which is why, for example Robbie Robertson made a shitload more money than the rest of The Band.