So it turns out that the blue channel in Dislyte's PBR maps is actually for controlling the emission intensity, and that the roughness map (green channel) isn't actually used (as the devs set it so it's always at full roughness).
So, by making a custom metallic map (which involves literally selecting all of the metallic parts of the character's model and separating them to make said texture), Freddy now looks pretty much like he does in the CG trailers for Dislyte. Well, as close as you can possibly get to that in Blender. The trailer's model is much higher-poly. (credit to @pinkniz for the CG trailer model's screencap!)
While talking about materials, here's another random fact: despite the character master material always being set at full roughness in-game, you might notice that you can see specular highlights, most noticeably with the leather pants Dark Wolf Freddy's wearing here. (credit to @me-and-freddy-xiii for this Dark Wolf Freddy screencap!)
You might be wondering: how can you get specular highlights without the material being smooth? The answer is rather straightforward: matcaps!
Matcaps are essentially these textures that contain a reflection capture of sorts, which is then applied to the material.
In other words, matcaps are a way to give a model specular highlights without needing to utilize roughness maps.
So yea, just some discoveries I've made regarding how Dislyte handles its PBR material maps over the past week or so.