This is a question about the frequencies that remain on the string during the decay of vibrations. As I understand it decay occurs because of the:

a- Internal damping of the string. This is due to the friction between material that make up the string).

b- External damping. This is due to vibrations that are absorbed by air.

c- Damping by the guitar body. This is the useful work. Vibrations that are transfered to the top.

Rate at which "c" occurs depends on the impedance matching between the string and the guitar body. My questions concern "c":

1- Does "c" get partly reversed by the elasticity of the top. Ie. are some frequencies returned to the string or even got canceled by the vibrating body depending on the phase of the returned vibrations?

2- Since impedance depends on the frequency, do some frequencies on the string get dampened faster than others?

3- What other factor would determine what frequencies present on the string during the decay?