For audition, take out instrument one found in school (3,4)
I believe the answer is:
'one found in school' is the definition.
(school can mean a group of fish)
'for audition take out instrument' is the wordplay.
'for audition' shows a homophone (sound like) (audition can mean hearing).
'take out' becomes 'see' (see romantically).
'instrument' becomes 'bass' (bass is a kind of instrument).
'see' is a homophone of 'sea'.
(Other definitions for sea bass that I've seen before include "Marine food fish" , "Edible marine fish" , "Saltwater fish" , "one showing off plenty of scales" .)