Some additional elements.
Yes really, Morphagene! Perfect for getting dark moving landscapes and surreal textures. Ideally I should add a good reverb to it: there is a large choice in this area, and at all prices, but you would be interested in the Pico DSP. Its algos are excellent, it has saturations options (saturated reverb, overdrive/ bitcrush) and an unbeatable price-performance ratio.
Well, on the oscillator side: Manis Iteritas (I would’nt have advised you that beast for ambient...). Well known for its industrial and apocalyptic colors. Not very cheap. It’s still on sale but Noise Engineering is currently stopping its production... NATO required it this summer :))
About additive synthesis, there is the Telharmonic (‘3 Voice Additive Harmonic synthesis’): perfect for all kind of drones and many other things. There is also the 4ms Spectral Multiband Resonator...
BUT in order to complete your MiniBrute without spending too much, and next to your Morphagene (and a reverb), I would add instead these two types of modules: a complex oscillator (Twin Waves, or Plaits) and especially a wavefolder that would thicken and make any sound source much more beefy and aggressive (Fold 6 for example).
So in summary, and keeping in mind a reasonable budget: your selection plus Pico DSP, Twin Waves, Fold 6.
As our friend @farkas says: good luck for your mission ;)
'On ne devrait jamais quitter Montauban' (Fernand Naudin).