OK, I'm checking back in here to help anyone else who comes looking for Minibrute 2s Mod Wheel advice.
First things first: there is no Mod Wheel control as part of the 2s. It exists as part of the Minibrute 2 (the one with the keyboard) but not the 2s with the sequencer. I guess the thinking is that the mod wheel is a performance tool if you are 'playing' the synth, whereas 'sequencing' is a different style of use.
It WOULD be cool if it was added, but that looks unlikely, so I'm posting what I've learned:
1) You can use the Attenuator knobs in lieu of a mod wheel to add in modulation. This isn't as intuitive or comfortable, but it's your best bet for live playing.
2) You can use the 'VCA' section of the patch bay to create your own attenuation. So you can feed say, LFO 1 into the VCA 'In 1' jack, and then use the 'CV' jack to attenuate the LFO signal at the 'VCA Out' jack.
What this means in practice is that you can use any mod source (ie Envelope, LFO etc.) to govern the attenuation via the VCA. So say you want to add vibrato to longer notes, you can use a long ADSR Attack or a re-triggered ramp up LFO 2 to bring in vibrato from LFO 1.
NB from a DAW you can send 'Channel Pressure' as a Midi message and this will appear at the MIDI section 'Press' jack as a control voltage. You can then use the Pressure CV to attenuate the VCA, so you can program the equivalent of Mod Wheel use via your midi clips.
It's not ideal, but hope this helps someone out there.
(PS: if you're really fancy you can use the sequencer envelope attack as a VCA CV controller to bring in attenuation within a 2s sequence...)