Creating Roughness and Normal maps when they are missing

Material novice question- Importing a Maya FBX and materials only come in with a diffuse texture.
Are there any ‘tricks’ in creating Roughness and Normal maps when they are missing?

short answer, no.
long answer, you can open the diffuse in photoshop and guesstimate what the roughness would look like given the materials, shape of object, etc.
for the normal a similar approach exists where you generate normals from a diffuse. Various tools do this with mixed results.

Absolutely, but because texture maps are typically dependent on the UV maps you would have to use a tri-planar approach utilizing the world-aligned node in your material. There are tonnes of world aligned texture tutorials on YouTube.

Another approach would be to import your FBX in to a program like Substance Painter, there you would do whatever work that needs to be done with your normal maps and you would then import that back in to Unreal Engine once you’re finished.

Yes and no. You need to bake from high poly yourself for normal, if roughness isnt there, you cant.