The attached should answer your questions.
For Question 1
The first preset has 2 translators. The first translator sets the current outgoing MIDI channel for CC with note on but no output happens. The current channel is captured in global variable "ga"
The second translator take the incoming CC on any channel and sends CC on the channel last selected with the note-on that you pushed.
For Question 2 (disable first preset and enable-next one
Here we look at note on. and set the global variable gb so that on next note we know which note to turn off.
For output we send raw MIDI message for current note on and last note off.
In raw the MIDI 9x pp qq is note on where x is MIDI channel and 8x pp 00 is note of where x is MIDI channel. This is all in hex. Note number is pp and velocity is qq.
Beware, however that there is nothing here to stop hung note-on. You didn't specifiy how you wanted to handle turning of the current note if another note is not pressed.
You may want to program something else to turn the last note off. In the meantime, turn down your speakers when testing this.
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