12-strings and classical nylon guitar simulator

Is it possible to add 12-strings guitar and classical nylon guitar sounds to Midi Guitar?

With MG you convert your normal guitar playing to midi notes, so with those midi notes you can play any synth or sampler and of course a good library of 12-strings guitar and classical nylon guitar of your choice.
Hope that answer your question.

Any library would you suggest?

There are many librairies trying to emulate acoustic and spanish guitars, not a easy task if you ask me.
Worse being us guitar players, for us I think its like doing virtual sex vs real sex, dont know if you know what I mean.
Also it would depend on whas your pourpose (front end guitars, solo guitar, comping guitars, there are libraries for different pourposes).
Anyway for nylon guitars the best I find is Ilya Efimov Nylon Guitar, it has a big sound with character and personality and does not sound fake to me (Im nylon player also).
There are many others. Of course for use any of those library you need to have installed Kontkat.
For 12 string acoustic I dont have first hand experience with any library.
There is an alterntive not MG related, but maybe the best for this type of emulation (guitar player trying to emulate another guitar) and it would be to use a GP10 or other Roland devices, where the acoustic guitar and 12 string guitar emulations are very good.

you may want to check out amplesound. There’s an acoustic one can demo for free, nylon and 12 string are $