Thanks for your reply.
Ofcourse, I hadn't given that much thought yet.
My initial idea was to buy a beatstep pro to sequence one or two sources and play the beatstep or the minibrute over that. But I'm not sure if that would be enough to run the system as is. It's quite a lot to get my head around at first.
Thanks for the tip on the filter, I'll ask at the store if it's possible to try some of them on the Troika!