Percussion.
Keyboard and harpsota can
keyboard
keyboard
No ... it is not a member of any "family", rather it has the distinction of being called "The King of Instruments" for a good many years. The organ has orchestral voices, but cannot sound like an orchestra itself. It's sound is unique only to itself and cannot be compared with any other instrument.
Harmonium
It is in the Keyboard family. Is that what you mean?
They are considered Bass because they hold the band or orchestra together.
The xylophone is a percussion instrument
The piano is a keyboard instrument.
The harp is a solo string instrument, BUT it belongs to the percussion family in the orchestra, as it is used mostly for special effects.
xylophone
The vibraphone is a keyboard instrument. But,sine you strike it with a mallet, it is a percussion instrument.