Well, er, we saw how it works already in the betas. Relics are the "in-game currency" to get vanity items for free. You use the relics to open a chest (it was about 50 relics?) and it gives you a random vanity item. You can find relics in matches or get them by completing the daily challenges (like get 10 kills with a certain weapon, win three deathmatches, etc etc).
If you have Naughty Dog Points (the actual money-bought currency) you can just choose what you want to unlock. There's no randomness. In the beta they gave everyone 150 ND points and you could buy about 1-2 things with it.
Don't see why they would suddenly change that system when it was the same in the last public beta.
Vanity items were only hats, taunts, and character skins (i.e Heist Flynn).
Weapons, Gear (stuff like the mine and grenade), mysticals, and boosters were only level-locked. Once you reached a certain level you would unlock those particular things for use.