For some reason, whenever I try to make a "new" hat entry, the characters wear it on their left ear. Even if I just open up the "ArmorCombatHelmet" and change it's ID to "ArmorCombatHelmeti," the new helmet flips sideways. What, if anything, am I doing wrong here?

Also, sometimes when I create a new NPCs, and I change their race to something other than Caucasian, their bodies remain Caucasian while the heads change. This is especially infuriating in that it doesn't happen all the time (just most). What could I do to ensure better results?

For future reference, questions about anything that requires you to use the G.E.C.K. go in the G.E.C.K. forum section

You need to update the character, so to do this:
-Click Character in the menu section at the top.
-Scroll down and click on Update FaceGen model availability.
-Done and test.

I wish I had an answer for you about the race, I would like to know how to match up the skin tone with the face and body as well

If the race thing happens in game and not in the GECK, run Master Update. That fixed that problem with a few mod-added NPCs for me.

I wouldn't mind if a mod moved the thread. I honestly have no idea how I missed that section.

However, this advice did fix the hat problem, thank you!

Unfortunately, the race problem is occurring in the GECK as well. The especially weird thing is that it changes correctly if I switch the race to, say Hispanic Raider or DLCAfricanAmericanMut (or whatever the diseased texture from the Pitt is called), but just as soon as I switch it back to one of the basics, say Asian or AsianOld, it goes back to Caucasian body. And again, once in a great while it'll actually switch correctly. Play testing reveals this also isn't just a hiccup in the GECK render preview: their skin tones are all weird in-game, too.