Yet another Arduino synth. Can a Nano handle it?

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Hi, I've been planning a portable synthesizer, something beetween a Shruthi and a Microkorg. I mainly play with keys and knobs, so seqencers and arps are not super important to me, I need 2 detunable oscillators and a CV out however, it seemed to me that an Arduino would be just the thing for it. So I wrote down my project goals in three versions: BARE BONES, STANDARD AND DELUXE. I'm askin you guys to evaulate feasibility of each version WARNING, LONG POST!

Arduino NANO:
BARE BONES VERSION
In this version Arduino only provides two square waves and CV out (for filter tracking and maybe drivin some analog vcos in the future). All waveshaping, suboscillatorS, sync, filtering and other stuff is done externally with analog means. The Synth is not interfaceble with anything like MIDI IN or analog sequencer. These are just totally basic features without which this project does not make sense to me.

Inputs:
1.9x5 keyboard matrix, 37 musical keys from F to F, 8 connections unused perhaps available for octave range switching, and some other functions
2.pitch wheel (up to +/-1 OCT)
3. OSC 2 Detune knob (with range of +/- 1 octave)
pitchbend will be read by an ADC with 0-5V range, so this input can also serve as global pitch CV input

OUTPUTS:

  1. 1V/OCT CV (just the keys or keys+pitchwheel, switchable)
  2. 2 square wave oscillators, master osc + 2nd osc detunable with detune knob mentioned earlier
  3. Gate out
    All outputs except for gate realized with PWM pins of the arduino, I think the 16bit timer should be enough for accurate CV, right?
    separate outs for each oscillator
    I don't mind buying DACs but the less ext ICs, the better

STANDARD VERSION:
Here there are selectable waveforms, mod wheel, and some other functions. Mixing will be analog, as well as filtering, VCAs and so on. MIDI OUT is here so that the synth can also act as a controller, so it outputs control voltages, audio and MIDI at the same time. I was wondering however if it would be possible (feasible?) to implement MIDI this way:
Keys+PBend+mod+wave selection+whatever -> Arduino reads it all and converts to MIDI messages
-> then INTERNALLY controlls oscillators and so on with these MIDI commands and outputs MIDI as well through a digital pin. Such an implementation would allow for external MIDI in control with pretty
much anything. This STANDARD VERSION contains features a bit more advanced than BARE BONES, not exactly critical, but quite handy, and I think (maybe incorrectly) that all those tasks should not be too much for my 'Duino

Inputs:

  1. 9x5 keyboard matrix, 37 musical keys from F to F, 8 connections unused perhaps available for octave range switching, and some other functions like:
  • pitchbend range
  • oscillator sync
  • waveform selection
  1. pitch wheel (up to +/-1 OCT)
  2. Mod wheel
  3. OSC 2 Detune knob (with range of +/- 1 octave)
    pitchbend will be read by an ADC with 0-5V range, so this input can also serve as global pitch CV input

OUTPUTS:

  1. 1V/OCT CV (just the keys or keys+pitchwheel, switchable)
  2. 2 wavetable oscillators sine/triangle, saw, pulse, master osc + 2nd osc detunable with detune knob mentioned earlier
  3. 1 LFO (amount controlled with the mod wheel (read from the same wavetable as audio oscs)
  4. Gate out (with retrigger)
    All outputs except for gate realized with PWM pins of the arduino, I think the 16bit timer should be enough for accurate CV, right?
    separate outs for each oscillator
    I don't mind buying DACs but the less ext ICs, the better
  5. MIDI OUT - keys + oct range + pitchbend + note on/off messages, mod wheel

DELUXE VERSION:
Here are the features I can easily live without, but if they are possible without too much hassle, then I'll take them. mixing, filtering, amplifying and so on still analog.

Inputs:

  1. 9x5 keyboard matrix, 37 musical keys from F to F, 8 connections unused perhaps available for octave range switching, and some other functions like:
  • pitchbend range
  • oscillator sync
  • waveform selection
  1. pitch wheel (up to +/-1 OCT)
  2. Mod wheel (so a syncable and/or tap tempo LFO)
  3. OSC 2 Detune knob (with range of +/- 1 octave)
    pitchbend will be read by an ADC with 0-5V range, so this input can also serve as global pitch CV input
  4. MIDI IN as mentioned in STANDARD VERSION buuuuut with USB and DIN! Can the Arduino USB used for this?

OUTPUTS:

  1. 1V/OCT CV (just the keys or keys+pitchwheel, switchable)
  2. 2 wavetable oscillators sine/triangle, saw, pulse, master osc + 2nd osc detunable with detune knob mentioned earlier
  3. 1 LFO amount controlled with the mod wheel (read from the same wavetable as audio oscs)
  4. Gate out (with retrigger)
  5. Additional Pulse trigger out
    All outputs except for gate realized with PWM pins of the arduino, I think the 16bit timer should be enough for accurate CV, right?
    separate outs for each oscillator
    I don't mind buying DACs but the less ext ICs, the better
  6. MIDI OUT - keys + oct range + pitchbend + note on/off messages, mod wheel

hope this is readable