MF-102 isn't a bad choice, but I would check and see if its audio I/O can handle the synth-level signal or if you're going to have to restage the gain to match what the MF-102's input and output want to see. If it insists on line levels at input and output, adding an effects loop I/O module is easy enough and won't take too much space. Better still, Ladik's A-525 offers dual I/O restaging in only 4 hp so if you want to run two different mono effects boxes, that would make that happen. As for the CV connections, there's no problem there. The Moogerfoogers all use standard synth-level CVs and such for those patchpoints.
There's not so much a difference in quality per se between envelope generators, except for the obvious build quality issues that turn up all the time between different manufacturers. The differences that exist mainly have to do with circuit behavior...how the controls respond and what exact values are being set by them, can you change the overall speed of the envelope, exponential or linear, onboard inversion or not, stages, looping/one-shot, and so forth. These are not exactly problematic limitations, but more something you learn to live with and get used to how they behave over time. But it really is a matter of choice, and I've always found it interesting that so many people dote on the four-stage ADSR method when some classic, coveted synthesizers actually never used that; the Minimoog's EGs are actually three-stage (ASR) and much of the Buchla architecture revolved (and largely still does) around two-stage AD envelope generation. But they're all a bit different, and while having a couple of one type (or one of those being a slight variation on the other) is a good idea, having a couple more for somewhat different purposes is always a good idea if you can fit them in.