As I understand it, an exciter would emphasise (and where absent create) odd harmonics over every frequency present in the input spectrum, which would be a lot of frequency content you aren’t originally intending (eg. new odd harmonics over the existing even harmonics…).
I don’t really know what the state of the art is in polyphonic pitch tracking in csound, but I think tracking the base pitches and making their odd harmonics is the thing that would make musical sense here?
I guess a compromise would be to find a few prominmant spectral peaks (with more weight for lower peaks) and get harmonics over those? I bet some prior art exists for this.
Good luck, I hope someone more informed has a proper answer.