You cannot know what your textures should look like until you know what your rendering engine is (which includes the shader used.) You haven’t said-- it seems like you haven’t even decided.
Sometimes I make models for a really old rendering engine. This engine uses a UV mapped texture plus diffuse, emissive/ambient, specular colors. Diffuse + ambient use the same texture. The rendering engine allows for only a single dynamic sun lamp.
Do I bake lighting into the texture? I bake some lighting into the textures. I carefully tune my lighting for the bake so that view/lighting dependent effects exist, but are subtle. Do I bake specular? I mix in some specular. This gives me some variety in the texture so my ambient isn’t flat, but not so much that it looks out of place because the baked in lighting doesn’t actually represent any scene lights. Without baking in any specular, without any normal maps, I can’t suggest the same (false, fake) detail that I can by baking in a little specular.
Now, that old engine also allows for the use of custom shaders. Some of those custom shaders have different lighting models. When I make textures intended to be used with a different shader than the default, I do things differently. If I’m building for a custom shader that allows for multiple lamps and lamps of different types, allows for normal mapping, allows for world HDRI lighting, I might not bake in any lighting/specular.
SSS isn’t a view dependent effect, but it is a lighting dependent effect. Some rasterizer engines include some SSS emulation (like Eevee, for example.) This is very different than Cycles SSS-- it’s a trick, like most rasterizer things. You might bake some SSS into your diffuse texture to compensate for limited scene lighting. Depending on your shader, you might also bake SSS color, radius to a texture for it to use.
Roughness is not lighting or view dependent (unless you’re doing something really weird.) Any shader that uses per-texel roughness/gloss is going to use a static roughness texture.