Good point - again for this, filter cutoff knob position or MIDI CC value percentage of 0/max value # would be mapped to cutoff frequency Hz #.

And yes, envelope times have different transition formulas between points, like linear vs logarithmic, as you stated. But again, having a direct map for of just A,D,S,R ms times would give you a rough approximation of amp env, save you a ton of time, and honestly, just serve as a sanity check sometimes, when trying to recreate similar "classic" subtractive patches between synths.