esha

Performing Esha Salaah once the time sets in

Q: My question is about differing start and finish times for Salaah. The mosques I have near to me have different times for Salaah. For example one mosque start time for esha is 9:30pm and another is 10:20pm. If I usually pray in one mosque can I follow the timing for the other, again as an example I follow the mosque with the 10:20pm start but offer my esha prayer before that as the other mosque clearly starts at 9:30pm. Is this permissible?

Tahajjud Salaah

Q: I want to ask that if I fall asleep at night without offering Isha prayer (unintentionally) and then in the middle of night if I wake up, can I offer isha prayer and soon after that tahajjud prayer? Also, do I read tahajjud prayer before witr or after witr (completing isha prayer and then read tahajjud)?