Sorry for the delayed reply, I forgot I posted this :)
Thanks Jim & farkas for the very useful info. I've since thinned out my herd of oscillators, taking out the A-110-1, E350, and one of the A-110-4s. I've added the Nin expander to Zadar, and have discovered the joys of having an envelope ready to go on-demand. Tempted to add another if not for cost. Will likely add another Veils as well, and maybe a second Plaits if I see a good price locally. I've also moved the DFAM into the rack, and it's integrating well enough with the rest of the system, at least until I need more HP :D
Speaking of HP, I'm wondering if the Erica Black Sequencer is going to stay. On paper it seems to give me more than the Metropolix, but it's (to me) not as intuitive and immediate to use, so I've been using it more for MIDI-to-CV than as a sequencer. If I cut that out, is there an obvious candidate for taking in at least 4 channels of MIDI? Hermod looks like it, but is there something else I don't know about? I've tried the Doepfer A-190-4 and was impressed with how cryptic it was to set up.