Yes, it's not too simple, but replication is at very least tried and tested.
> Are there tools for integrating sensors like VR tracking and Kinect? What about adding real time point cloud data into the scene?
Yes, not sure about real time, but Unreal basically has support for everything somewhere.
> How do you tweak shaders? Is there a good guide to shader development that is Unreal Engine aware?
Yes. It uses a custom unreal syntax underneath, so it's not trivial but it can be done. The engine also doesn't really like you managing the shaders yourself, e.g. If you want to dynamically change/replace shaders the RHI does expose the functionality but it's buried under so many layers of abstraction it's quite painful.
> How do you delve into raw C++? Is Rust supported?
It is raw C++. I wouldn't bother trying to integrate Rust because it doesn't really like you doing your own memory management in the first place.
As a final comment, if you want to find out how something works, just read the source they give you. The documentation is genuinely shit, and most people online (including some Epic people who don't touch the core engine) don't seem to be particularly clued in. Some flows are quite well documented, e.g. Animation, but other parts of the engine basically aren't documented at all.
Also, don't implement anything complicated in blueprints. They're written once, read never.