Plonk and rings do similar sounds, i would pick one first and other if i really loved it.
Plaits is great for dronning and ambient, maybe not for usual bass and lead works.
Batumi is a great modulation source, dunno if you still need stages, i would pick one and then see how much you need more modulation later. Maybe save the space for some Evenlope generator, like Intellijel dual ADSR, or someone who does envelopes and modulation like maths or Intellijel Quadra.
Maybe uZeus+Tiptop 1000ma would be enough for this system and save one power supply.
Unless you really need oscilloscope, maybe Pamela´s wourkout would save more space instead of mordax.
Also i would probably look into more tecnho oriented modules, like Intellijel atlantis(sh101 techno goodness), acidlab m303, or some more traditional stuff for bass?