Plaits and the Basimilus have their own envelopes. But they are very basic. Your synth voice has its own envelope generator as well. If you're using the O_C as a sequencer, it can output its own envelopes rather than just gates.
I'd put the Pico FX back in else you have a very dry rack. Personally, I'd rather have at least one FX unit rather an extra ADSR in this set-up.
As far as VCOs... or at least oscillators, the rack has a A116, Basimilus, and a Plaits module. The KickAll can also be used as a pitched oscillator in certain circumstances.
For its size. You might be a little heavy on oscillators. But I wouldn't worry too much about that. You can always remove one or more of them and place in other modules that'll fit in the same space. If you don't mind reconfiguring your rack the times you're looking for more functionality and less voices. Just don't do it with the power on and connected.
If the O_C is not getting the job done for your sequencing needs, you can always add an external sequencer.