Well, there's the Erica Pico Out...that's a 3 hp stereo out module with a headphone amp. But trying to cram both functions into the same remaining 3 hp will be virtually impossible. The other idea would be to use a Erica Pico CV Mix...this is a DC-coupled 3 to 1 mixer, and with that you can mix both audio and control voltages. CV mixers have to be DC-coupled, since you can't pass extremely low frequency signals such as LFOs or DC voltage values via an AC-coupled mixer. Those are for audio only. The reason I'm suggesting that particular mixer is because you can use it for mixing modulation curves out of the Maths when you need to do that, or for an audio mixer when that's called for.
As for using the Moogs as outputs, there are several points into which you can patch on the M32 to put a synth-level signal into it as part of its signal flow. Probably the best points for audio would be one of the VC Mix inputs, probably the HPF patchpoint (Mix 2), as that lets you keep the low-pass engaged for your M32's signal and you can CV the mix between that and the audio signals on the rack. As for CV signal patchpoints...anything that notes that it's a CV function on the M32's patchpanel will take a CV or modulation signal. So for example, to modulate the LFO's speed you'd patch in a signal from one side of the Maths, set that up with the slopes you want, config it to loop, and then your M32's LFO time is sweeping up and down. The DFAM has similarly-usable patchpoints on it also. Not quite sure, however, if the Moogs want to see line-level audio or synth-level at their "Ext Audio" patchpoints, but a bit of experimentation can sort that out.
Best thing I could suggest is: study this site. This pretty much IS the compendium for everything modular on the Internet with the exception of cases, which are one of the few parts of a modular synth that MG doesn't cover. But if it goes IN the case, 99.9 times out of 100, it's here. But read up on what the basic modules do, for starters. Muff Wiggler: also helpful, plus spending some time on Doepfer's website seeing how their modules function (Dieter is good about going into detail) isn't a bad idea at all.
As for taking up space, you will find...sooner or later...that electronic music equipment somehow breeds like rats and overtakes everything. Expect it.