this is actually pretty simple 
within the organelle pure data patches both midi and the organelle keyboard notes key converted to a send called notes , which are received with [r notes]
so this note is a midi note, so notionally its an integer, but it is interpreted as a float, a fraction - so 60.5 is valid - this is then usually converted to a frequency using [mtof]
so:
a) there is a mapping from a fractional note to the frequency often by mtof
b) fractional notes are fine
this means there are two ways to do microtonal mapping
a) your micro mapping goes from notes to frequency, so replaces mtof
this means going thru every patch, at replacing mtof with your own microtonal mapper
i.e [r notes] → [mtof]-> [oscillator], becomes [r notes] → [micromap] → [oscillator]
b) your micromap goes from notes to notes, just rescaling etc.
this is actually probably the better approach.
basically take the midi note, and remap them to your microtonal scale.
i.e. [r notes] → [micromap] → [s notes] (this wont work but is the idea 
)
the great thing about this approach is
for normal patches you can do this in mother.pd, so without touching the patch code!
for orac, you could create a midifx module, which does it … so would work for all synth modules, and even work with sequencers etc
of course for bonus points, create an orac module that interprets scala files and uses these as the mapping.
this is the ‘same issue’ as expressive controllers, and so the approach is the same…
you indeed use pitchbend, but you would put each note on a separate midi channel.
this of course, requires that your synth is MPE aware… though you can do it with a multtimbral synth by loading the same patch on multiple channels.
inaccurate - done know who told you that, they are talking nonsense;)
PB is 14 bit, so there is plenty of resolution for microtonal , as that 8192 steps per semitone
(for expressive controller its less than that, since we want to slide over at least a couple of octaves, but even that is absolutely fine!)
modular, it would really be audio as such, it would have to be DC coupled.
and then it depends on the resolution of the DAC, but it probably be 24 or 32 bit, so a bit higher…
the main thing about modular though, is it not midi focused, CV pitch is just voltage, so (except midi modules), things like oscillators are assuming continuous voltage not ‘steps’.
but its expensive to start building a polyphonic modular, microtonal or not
so… not really better, just different.