Android USB Accessory as a Device?
It cannot. Most devices are not designed like that. You could avoid usb issues by using Bluetooth instead. And as far as I know, AOA is out dated and not very well supported any more. It stagnated with kit Kat and universal OTG support.

As mentioned though, a USB HID device will always be a slave to the host. For HID, which is a predefined USB standard and not an arbitrary device that requires custom drivers, USB OTG is what you want. Power will be available to your device.