The other module i would recommend for this is the Befaco Percall, I don't own it but you can make anything into Percussion with that and it also has Choke so it will shut off the Open Hat with a Closed Hat etc.
-- wishbonebrewery
Thank you, that looks seriously awesome.

As you say you could use an envelope follower which is listening to some other percussion track to get Triggers, gates and a Decay envelope out of it.
-- wishbonebrewery

OK, that's what I was wondering. But I'm still struggling to grasp the basic (starting) signal flow when there is no oscillator involved. Will this work conceptually? Or do I ALSO need to extract a gate signal from the envelope source and feed that to a gate between "continuous audio source" and the VCA?

Audio source -> VCA -> VCF -> final audio output
Envelope output -- ^ ------^

I'm trying to get into this as cheap as possible haha. And add stuff later.

Thank you!