1. You are correct that CCG3 is not supporting drag a USBFS component in TopDesign.cysch.
2. Since I noticed that you are using CYPD3120, you use based on example code of CYPD3120-40LQXI_dp_dongle in the SDK3.0.2 and add customize for your design. By default, CYPD3120 example code have implemented USB HID and Billboard. You could get details information in the files of below:
Could you send me code example how this is implemented?