I'm also going to agree with Curt on the CCC count.
On the dimming isue - I assume you have the job and looking to hold a price you bid sans going negitive, or low $?
I do a lot of dimming panels in residential - which is different due to the lower loads.... ( i.e. 4 300-500w loads off of a 20A circuit... ) I bundle them up - sure why not, each load is only a few amps each....
In your situation you'll need to derate in the first place (2-two-wire ciruits is more than 3...), and the loads will be high across the board. And since it doesn't sound as you have too much in way of choice of respec'ing the lighting or controls to say some sort of 0-10v dimming product??? Or 'shoe box' (Remote) DMX controlled dimmer?
I ran circuits for a few of these a few years back - it took 2-roundhouses each. Which is an effective way to get the power up there as a MWBC - closer to the loads, where they should be. That is if you have a place to put them????
Either way sounds like a gutter job and spliting out of that to me - at least from my comfy chair....