This dua “Alhamdullilah alladhi la yuhmadu ‘ala makruhin siwah” was not narrated from the Prophet Muhammad (peace and blessings be upon him). It is better to say ‘alhamdulillah ‘ala kulli hal’.

1. There is no du’a to be recited before the adhan. 2. There are no specific words to be recited before the iqamah. 3. Du’a is highly recommended between the adhan and the iqamah. 4. There is no du’a after the iqamah. 5. It is Sunnah to repeat what the muadhdhin is saying. For more, see the detailed answer.