Hi Roderick,
The SATA connectors are entirely separate from the M2 slots, (see attachment 1) and from what I have been able to find out you can have 2 sata disks and 2 M2 sticks all working together.
The USB might be a problem but on all the other ASRock mini-itx boards that I have used (AM1 socket) they have dedicated USB 2,0 sockets where they say they do. If that holds true for this board then the USB 2.0 socket on the rear panel should work with a USB 2.0 Y cable for keyboard and mouse. Checking on the bios setup there is a switch to allow win7 USB wake support and since win doesn't come with USB 3.1, I think we can assume the USB 2.0 ports are real USB 2.0 as allowed for in the chipset tables.