In essence you don't need to overclock your CPU and thus have no need for a K suffixed processor. All you'll have to do is go into BIOS and enable X.M.P profile and reboot system, check for any errors with stress testing and if no errors come up, you're good to go. I would highly suggest that you're verified your BIOS is up to date.
There is no problems with buying rams that aren't in the QVL but make sure you buy kits instead of mismatched sticks of ram.
Further reading:
http://www.tomshardware.com/answers/id-1740132/installing-2400-mhz-2133-mhz-ram-4770.html
http://www.tomshardware.com/answers/id-2867815/2400mhz-ram-cpu.html
https://www.techpowerup.com/forums/threads/do-i-need-to-overclock-my-cpu-to-run-2400-ram.192420/