Here are some of the synth patches we used for the track, starting with the pluck synth playing the main melody:

-- trance style fm pluck
-- brightness adds harmonics
-- timbre adds detune
-- time elongates the pluck-like amp envelope
-- fx adds an upper harmonic, creating a bell like sound
fpluck brightness timbre time fx = 
    s "superfm"
    # amp1 1
    # amp2 0
    # amp3 0
    # amp4 0
    # amp5 0
    # amp6 0
    # ratio1 1
    # ratio2 (2.007 * (1-(timbre*10))) 
    # ratio3 (2.000993  * (1-(timbre*10))) 
    # ratio4 0.005
    # mod12 (1.9 * (brightness*1.5))
    # mod23 0.3
    # mod34 0.9
    # feedback ((brightness*0.5) + range 0.0 (fx*0.8) perlin)
    # mod33 2.8 
    # mod44 (fx*5)
    # egrate11 10
    # eglevel11 1 
    # egrate12 (0.1993 * (((1-time)*1.75)))
    # eglevel12 0.0
    # egrate13 10
    # eglevel13 0.0
    # egrate14 10
    # eglevel14 0.0
    # egrate21 10
    # eglevel21 1 
    # egrate22 (0.993 * (((1-time)*1.75)))
    # eglevel22 0.0
    # egrate23 2
    # eglevel23 0.0
    # egrate24 10
    # eglevel24 0.0
    # legato 2
    # rel 0.9

For the fm reese bass, we also used FM synthesis:

-- REESE
-- timbre adds detune
-- fx modulates timbre
freese brightness timbre time fx 
    = s "superfm"
    -- voices
    # amp1 1
    # amp2 0.8
    # amp3 0.8
    # cut 1
    -- ratio
    # ratio1 2 
    # ratio2 (0.99 + (timbre * 0.05))
    # ratio3 1.008 
    -- fb
    # mod11 0
    # mod22 1.8
    # mod33 1.6
    # feedback (brightness + (range 0.0 fx perlin))
    -- mod
    # mod21 (0.1 + fx*0.2)
    -- time (reese doesnt need time)
    -- fx
    # shape 0.3
    # triode 2

For the counter melody, I designed an analog-sounding synth voice in SuperCollider:

// "25midi - Aura" pluck style synth voice
(
SynthDef(\aura, {
    |out, att=0, dec=0, sus=0.5, rel=0.7, curve=0, lfo=0.7, detune=0.2, vcut=1.0, vcutmx=0.5, vfx=0, sustain, pan, freq|

    var phaserEffect;

    // AMP ENV
    var begin = Impulse.ar(0);
    var env = EnvGen.ar(
    Env.adsr(att, dec, sus, rel, 1, curve),
    Trig.ar(begin, sustain-rel));

    // OSC
    var pwmMOD = LFTri.kr(lfo);
    var sound = (Pulse.ar(freq, pwmMOD*detune + 0.2) ! 2);

    // FILTER ENV

    // first, remap vcutmix so we only get values between 0-1
    var remappedVCutMx = vcutmx.clip(0.0, 1.0);
    // create filter envelope, use vcutmx to mix the envlope in/out
    var filtEnv = XLine.kr(1.0, remappedVCutMx.linexp(0.0, 1.0, 1.0, 0.01), rel, doneAction: 2); // vcutmx scales the envolope
    // set the the envlope strength 0=full pluck, 1=open
    var remappedVCut = vcut.clip(0.0, 1.0).linlin(0.0, 1.0, 0.01, 0.99); // Remap vcut values to [0.01, 0.99]
    sound = LPF.ar(sound, 20000*remappedVCut*filtEnv.linlin(0.0, 1.0, 0.0, remappedVCut));
    sound = sound * env;


    phaserEffect = AnalogPhaser.ar(
    sound,
    SinOsc.ar(0.22),
    skew: SinOsc.kr(0.059),
    feedback: SinOsc.kr(0.005, 1pi).range(0.0,0.85),
    modulation: SinOsc.kr(0.0192, 2pi).unipolar,
    stages: 50
    );
    sound = XFade2.ar(sound, phaserEffect, 2 * vfx - 1); // Blend/mix the dry/chorus signal based on vfx

    // adjust vol down a bit in relation to other sounds
    sound = sound*0.7;

    // OUT
    OffsetOut.ar(out, DirtPan.ar(sound, ~dirt.numChannels, pan));

    }).add;

    ~dirt.soundLibrary.addSynth(\aura,
    (instrument:\aura, att:0, dec:1, rel:1, legato:1, sustain: {
    (~delta*~legato).max(~att+~dec)+~rel}));
);