Installing a title from a different region (with the exception of certain titles with the same ID across regions, such as Pokemon games) will do nothing of note, aside from maybe flagging your console if you go online. It won't show up on your home menu at all; to access it, you'd need to convert your sysNAND to the same region as the game. To convert it you'd need a SecureInfo_A file for the region you're switching to, and that contains console-specific information - in other words, it's also possible that it could flag your console for a ban.
As for emuNAND, for all intents and purposes it's a copy of your sysNAND running from the SD card. While launching it in Gateway mode or CFW will patch some region/signature checks, it's still as region-locked as your sysNAND. Launching it in Classic mode or through rxTools is essentially the same as sysNAND - no checks are patched out, meaning you can't launch games from other regions. Some of this might be wrong in regards to region-free carts, though, since I don't pay much attention on that front.