２) Is there a difference between wood for earphone enclosures and wood for musical instruments and speakers? (On the difference in sound of wooden enclosures.)

There are many types of wood as instruments.
Each has a different role for the part of the wood used.

Speakers and headphones are a little like earphones, but earphones have a special structure with an enclosure in front of the drivers.

Therefore, if a particular wood used in a musical instrument, speaker or headphone were to be used in the same way in an earphone housing, it does not mean that it will sound the same as those.

Also, earphones are very small, so it is possible to use wood that cannot be used for those earphones.
In the case of earphones, there is a larger selection of woods to choose from.
This is a very big advantage.