I started to toy with this a little.  MIDI Solutions Event Processor (Plus), with pseudo-random variables.  I don’t see a way yet to trigger the sequence with a adequately long delay timer.  This kind of approach would have to use a switch action.  Maybe momentary / latch configs to differentiate between the next random seed & locking in the current one.

Random (pre-programmed & saved) presets would be easier to implement, but arguably less useful that preset parameter randomization.  And I agree that some parameters would have to be limited to a certain fail-safe range of values [MIX, FEEDBACK, et al].