Hi
Yes, you need a PC adapter for each of Kinect devices (unless it's a Kinect v1 for Windows device which does not require a separate adapter).
If you use Kinect for XBOX One (Kinect v2) then you also need 2 PCs for recording as MS Kinect SDK support only 1 sensor per PC.
http://docs.ipisoft.com/Distributed_RecordingFor PS Eyes you need some
active USB 2.0 extension cables. Search for "USB 2.0 repeater" at Amazon. The number and lengths depend on your setup - size of the room, location of recording PC etc. Typically (single recording PC near capture area), for 6 cameras you'll need 2x 10m cables, 2x 5m cables and possibly 1-2x 3m passive cables.
Also, to get full 60 fps, each pair of PS Eye cameras needs to be connected to a separate USB controller. Given that your PC only has 3 USB ports (is it a laptop?), there are only 1-2 USB controllers available, so you need to get additional USB controller(s). For desktops we recommend PCIe cards based on NEC USB 3.0 chips. For laptops the only extension option we know is an Express Card to USB adapter, but it's not availble on modern laptops. Thus, for recording with 6 PS Eyes you'd better use a desktop PC or a couple of laptops and distributed recording feature mentioned above.
If you've got enough USB controllers (3 for 6 cameras) but insufficient ports, you may use USB splitter(s) to get additional ports.