I am going over all the controls and settings of the FM envelopes on the digitone. I am trying to come up with some practical examples where each of them can be useful and I am jamming for a bit with what that led to.
no, the LFO can't trigger the amp envelope. the FM envelope can be either a short trigger or a gate (with the sustain stage being as long as the gate). The amp and filter envelopes always behave like the latter if I'm not mistaken. For the amp env you only get to chose wether it should retrigger with every trig or always go through one entire cycle first.