It's possible that I misread the specs, but Weather Drone seems like it's a full synth voice. If that is the case, all it really needs is a Keystep (or Beatstep) to get bleeping/blooping melodic note sequences right away. It could be done with the Keystep's onboard sequencer, or drive the Keystep CV outs from Ableton
The output module is nice if you want to connect headphones directly, but it's not necessary if you already have a mixer or sound card for your computer.
A basic synth voice would be:
Oscillator - Filter - Envelope - VCA
All of the above appears to be included in Weather Drone along with an LFO, sample and hold and some other nice bonus stuff.
If you want to keep sequencing in the rack. Check out the full line of Pico and Ladik modules. They have some great budget minded gate and CV sequencers.
Pico Seq is a personal favorite of mine.