I figured out who the five PROJECT skins are

Alright, let's do this:

1. Yi or Xin: Although Trace 1's "Trace Lost" gives us nothing to go off of, I believe the face in the preview image is one of these two. LOLNOPE, it's Jax. I correct myself.
2. Leona: Trace 2 mentions a female "protector" with many light-themed descriptions. In addition, IronStylus mentioned that he wanted a cyber Leo skin at some point iirc.
3. Lucian: For Trace 3, words like "purity", "blazing" and "piercing" reflect his abilities directly. Also confirmed to be male, that fits.
4. Zed: No duh. "Shadows marked, death lives besides". Death Mark. Come on Riot.
5. Fiora: Mentions a gleaming blade, references her ult ("orbiting"), "blade dancing", etc. Also, Mecha Fiora would be too obvious of a reference for this skin, so only the real JRPG fans fans will get this one (I for one played that game and am now hyped as hell).