Two days and no suggestions makes Eric a sad panda.
Here are some suggestions to get us started. A rough unpolished list of topics/ideas to cover. 
Post Process:
- Why does my scene get brighter? Turning off Eye Adaptation (Auto-Exposure)](https://docs.unrealengine/latest/INT/Engine/Rendering/PostProcessEffects/AutomaticExposure/index.html)
- Using Post Process to give some control over lighting in a level.
- How to add or remove more JJ Abrams (Lens Flare) in your scene?](https://docs.unrealengine/latest/INT/Engine/Rendering/PostProcessEffects/LensFlare/index.html)- Why is there no post process effects in my scene? Engine Scalability
- How to make the post process affect the entire scene without scaling the volume? Unbound check box
- Some examples or situations with Blendables for post process. Enabling and disabling them for effect.
- Overview of Bloom Settings for better control of your Bloom output
- Controlling Light Propagation volumes (Link back to Wiki Lighting Guide for some information there as well)
- Anti-aliasing tips and issues
- Animorphic Lens Flare (not possible…yet with PP) particle example to demonstrate
- Screen Space Reflections tips
- Modifying Post Process via Blueprints
- in UDK I used post processing mixed with Scene depth priority to achieve certain fx. since SDPG is gone now, what other strategies can be used to tackle draw order?
- how to properly use multiple postprocess materials as blendables. Is there a way to give them different weights or something like that?
Docs:
https://docs.unrealengine/latest/INT/Engine/Rendering/PostProcessEffects/index.html
Cool post process setups:
https://wiki.unrealengine/GameBoy_Post_Process_Effect_in_UE4
Materials:
- What does Specular do in a PBR Material?
- which textures can be used in a material/are required?
- what shall I do with an albedo, glossy,… texture?
- whats the difference between a shader and a material?
- why is my material stretched when I apply it to my mesh?
- Why is my texture so big/small on my mesh? texture coordinate node)
- World-based UV applications? i.e. tiling /blend based on distance? (ie. Landscape blend distances, etc)
- Forward vs Deferred examples: UDK vs UE4. What’s the deal?!