Hi
First I would you read the the MCUXpresso SDK USB Stack User's Guide.
Section 4.1 Developing a New USB Device Application.
Section 4.2 Developing a New USB Host Application.
From software perspective, if you use host cdc as a starting point , see below picture, you need to copy device stack to the usb folder, copy the device cdc source files to the sources folder. Next you need to merge main function. Maybe you need at least 2 tasks, one is for cdc host, one is for cdc device. and start the relative task when needed. Maybe need lots of time to fix some compile errors.

Regards
Daniel