The more introverted child who likes to draw and to look or read books may enjoy the piano. Guitar is a quiet instrument. The register of the instrument is also a factor. Some prefer high pitch sounds, often meaning a melodic instrument like a flute, and some prefer low sounds such as the cello or bass. These preferences all help in making a sensible choice of instrument.
Reputation is important.
Hearing from other friends that a certain teacher or school is good is an excellent credential. If there is no recital, that is very strange. Depends on the age and level of the child, but daily practice is very important. However, extremely short practice sessions are important. We talk a lot about the home practice in our parent seminars.