1. What would be the estimated duration of awal waqt namaz? Like 10 minutes of Azan or 15?
2. How to pray The Qadha of Tahajjud ? Should we include all the Rakats (sunnats also?)

1- First 10 minutes
2- Yes include all rakaat if unable to recite then minimum pray 2 rakaat namaz e shafa and 1 Rakat namaz e witr.