Does this unit have enough power for operating with a USB 2.0 Female Type A attached?
Yes, the unit has sufficient power to operate when attached to a USB 2.0 Female Type A. However, the transmission speed may be limited as a result.
No, additional power is not required if the male USB 3.0 is only plugged into a female USB 2.0. The Type-C (USB 2.0) for DC 5V input is an alternative option for powering on the adapter without using the USB-A connector.