Hardware Selling my Wii U, what should i do with my NNID

[Range-TE]

Hi guys, just need some advice here.

I'm selling my Wii U, and ofcourse i'm gonna un-link my NNID, but i do want to keep DKCTF, MK8, and MH3U on there just to include it alongside my physical games when selling my Wii U.
Is it possible to un-link my NNID and keep those games installed? another solution i thought of would be un-linking my NNID, then installing them through mocca cfw, because it is a modded wii u

actually that would be another question, what does un-linking my NNID actually do to my Wii U ? Will it delete every downloaded games and DLC ?

thanks in advance guys!