It is permissible for the individual to depend on his parents in finding out the most knowledgeable if he trusted their choice to be in accordance with the religious guidelines – e.g. referring to the ahl-ul-khibrah. If he does not, then he should do his own research based on those guidelines.
The adhan is recommended in the daily prayers. However, if the Asr or Isha prayer is performed immediately after Dhuhr or Maghrib prayers, the Adhan is not legislated, so the iqamah alone can be recited.