For the 1st warm-up, try the bench strength. For the 2nd warm-up, play a team as close to the best XI as possible.
I would go with this for BD warm-up:
Azhar Ali
Fakhar Zaman
Mohammad Hafeez
Shoaib Malik
Haris Sohail
Imad Wasim
Sarfraz Ahmed*+
Shadab Khan
Fahim Ashraf
Wahab Riaz
Junaid Khan
This XI for Aus. warm-up:
Ahmed Shehzad
Mohammad Hafeez
Babar Azam
Haris Sohail
Shoaib Malik
Sarfraz Ahmed*+
Imad Wasim
Wahab Riaz
Mohammad Amir
Hasan Ali
Junaid Khan