RE: drummers, it may well be a misapprehension, based on the limited examples I’ve heard but my impression has been that Gadd is a bit "flashier".
I wonder if anyone in the audience at that L. Ronstadt show had any clue whatsoever re: what sort of player Grolnick was.
Can you recommend some M. Brecker recordings that are in an all-acoustic, mainstream Jazz vein?