Tones and harmonics get clustered into pitches, e.g. mistuned harmonics as seen in bass guitar or piano still get decoded into pitches via some sort of best match if the mistuning does not exceed certain percentage. And it works even if some harmonics disappear and reappear.
this is correct, and the reason we are tolerant is because of dispersion: even though the different harmonics are present on the same string of the same length, the resonant frequencies don't need to be integer multiples of the fundamantal since waves of different frequency have different propagation speeds on the string.
in the case of bowed strings mode-locking ensures the phases of all the harmmonics are reset each cycle (the bow sticks and slips), so that bowed instruments can be played harmonically to parts per billion.
since a lot of sounds are plucking we must be tolerant for frequency dependent propagations speeds in regular strings / media
In the case of either the 2 strings being bowed vs the 1 string, there is an actual underlying reality, that can not be deduced from the limited information available in the sound, so any guess risks being an illusion (with probability 50%).
Assuming we agree that "illusion" merely means mismatch between interpretation and reality.
The pitch is higher level than purely perceptual.