Can an Arduino Pro Micro act as a USB hid and usb host device at the same time?
Theoretically, yes. The usb host shield off loads some of the usb logic, freeing up the microcontroller to do other things. But both the host shield and the usb hid v-usb code are processor intensive, and you may find it difficult to do both host and peripheral at the same time due to memory and code space issues as well as strict timing requirements . Your welcome to try though.