Pulling them out of their boxes and into a rack makes the most sense for my live setup, and I'm straddling between hardware and modular, so would prefer to start with some semi-modular units at the outset. Maybe pull them out if things grow from there.
Idea behind the compression is similar to how the sound sources would run on a digital mixer or DAW. I was sort of considering the MB2, SV-1, and DFAM as their "own" soundsources that are coming together to make some kind of performance. So mentally I have them each on some kind of "channel" that has compression and eq to have them sit together nicely. There's also the ability to sidechain. In the bass example you give, sure, there's a hard hitting bass that goes from -80 to 0, but anything else that comes at the same time is going to clip it -- particularly a bass drum. I use compression for evenness and gain control.
The master, stereo compressor is a glue compressor that can also add some saturation and take out any stray peaks. This sort of gainstaging is pretty common in production setups. I just don't know how it translates to modular. I'm trying to imaging what I'd be doing if I had something like the MB/SV-1/DFAM running their final outputs into Ableton.
Does that make sense?