Dr. Foo, you asked about mixing a deep bassline with a deep kick. I don't know what freq pm'ed you about, but this is what I'd try: stick a gate / ducker on your bassline, and trigger it with your kick. That will let the bass run full-on when the kick's not there, and when the kick drops, the bassline will be temporary turned down, to let the kick shine through.
I wouldn't mess around with the stereo field too much... I think you'll want your bassline and kick panned center. (Ever heard a bassline or kick panned off-center in headphones? Sounds really weird, I think.) No doubt you could EQ it up too, but I don't know enough about EQ'ing to make any particular recommendations.
Freq, so sorry if this steps on your toes. But to continue your "people talking in a room" analogy, if someone asks a question out loud, and the answer is whispered in their ear, that just doesn't sit right. This is an open conversation.
Mic Pro Crusher, working with both Agnostic Front and Run-DMC isn't that odd. Rick Rubin worked with Johnny Cash, The Beastie Boys, and Slayer. A good engineer's going to know what to do. Besides, both came out of NYC at the same time, in similar depressed conditions.