Hi! Not much more to add to this i guess, as so many already gave you the answers, but i also understand that the MD works closely with the lead performer and determines what they want the songs to come off as (different arrangements then the studio versions possibly, different key and speed to be played etc), and things like that. Also they may have to work with the lighting director, choreographer (if the artist has one! and by the way, choreography isn't just dance, it is even how the artist will walk to certain designated spots in a song, its a lot of stuff; anyway, i digress....), etc and coordinate the songs together as a whole.
I recall Meat posted here when he was sick from his first surgery, that he was in regular contact with Kasim and Billy about how he wanted certain things to come off onstage, and i believe it was also indicated somewhere, probably not by Meat(I forget where it was exactly said), that Kasim has been with Meat for so long that he basically knows what sound arrangements Meat prefers for the songs and gets the band working on those, but then when Meat comes in for rehearsals, there may be a few minor adjustments and then Kasim and the band work from there.
Edited to add: Winston,
I dont know about Kasim getting the band set for breakfast, but once upon a time many moons ago, Steve Buslowe had discussed his 'dilema' of the evening with me before a show -- whether he should get the band Chinese or not! :) Its been a while, so I may remember this slightly wrong, but i think he went on to say that when they're on the road and stop to eat, its his job to figure out what and where. Im sure that's changed since.
Take care!!
Jen S.