Here is a list of all the skins in the game pretty much, including the unlockable ones. Not mentioned are the Liquid Metal Lancer which you get with the purchase of the Season Pass. The bottom 22 skins though, are attainable by purchasing them on Xbox Live on Day 1 of release (September 20th). I’m thinking maybe 800 Microsoft Points for all those bottom skins but hopefully it more like 120 Microsoft Points since they are just weapon skins!
Crimson Omen- Hammerburst/Retro/Gnasher/SOS from doing things in-game.