To recite Salaah and salaam or any Durood Sharief specifically before Azaan has not been proven from any hadith and therefore will be contrary to the Sunnah. However, to read Durood after Azaan and thereafter make dua is proven from the hadith. Everything we do should be according to the Sunnah, (Fataawa Mahmoodiyah vol.15 pg.87).
To make Zikr after Farz Salaah or any other time is meritorious. However, to deem the recitation of the 1st Kalima thrice, specifically and necessarily, will be a bidah and a sin.
and Allah Ta’ala Knows Best
Mufti Ebrahim Desai