Last tested: Apr 7, 2020
Besides the general scheduling permissions, you need the develop permission on the model where the datagroup is defined AND see_datagroups. This means that only developers can schedule based on a datagroup.
You do NOT need
update_datagroups —this permissions is only for seeing datagroups in the Admin panel.
Changes from Version 7.8+
Non-develop permissioned users can select "Datagroup Update" when defining schedules.