In the Name of Allah, the Most Gracious, the Most Merciful.
As-salāmu ‘alaykum wa-rahmatullāhi wa-barakātuh.
According to the Hanafi and Maliki schools, it is permissible to stipulate non-existent beneficiaries as future beneficiaries of the Waqf. The scholars state that if an entire Waqf is stipulated for a non-existing beneficiary, then the Waqf will temporarily be allocated to the poor and needy until the beneficiary is born [Hashiyah Ibn Abidin]. This is also the view of the AAOIFI Sharia Standards.
And Allah Alone Knows Best
Mufti Faraz Adam,
I Waqf Shariah Advisor