EricNS

For correct compositing, the object buffer uses the transparency of the materials. That's the reason why your buffer is 50% grey.
 
If you need a totally white mask, you could either:
 
-Filter your current buffer layer in Photoshop (increase the exposure or play with the curve to get a black and white mask)
or 
-Render a new mask in Cinema 4D, using a Compositing Matte Object.

If you need a stronger indirect illumination with the Physical Renderer:
 
-You can increase the Intensity and Saturation of your Primary and Secondary GI Method. 
-You can increase the Generate GI in the material "illumination" parameters.
-You could also add luminance to your material.
 
The reflection won't have any effect on the Global Illumination (but on the caustics).

https://support.chaos.com/hc/en-us/articles/4954081899793-How-to-use-Corona-Decal-object-in-Cinema-4D-

It's only scanned models animated with Mixamo (I recognized the mocap directly) and duplicated with a cloning/particle system. There's nothing really "procedural" about it.
 
It can be done manually in Cinema 4D, for free and relatively fast.
 
The easiest way:
 
1. Create your characters and looped animation in Mixamo (https://www.mixamo.com/).
2. Export them in Fbx.
3. Load the files in Cinema 4D, adjust the textures, make variations (colors, scale, speed, ....).
4. Clone these characters with Mograph or Xparticles.
 
You could also use the characters in Cinema 4D's asset browser (Models > Humans > 3D people), load and animate them in Mixamo.

Unfortunatelly, that won't solve the issue.
 
The shape of your geometry will still change from one frame to another making your texture stretch and slide, whatever the projection.
 
Could you send a simplified scene ? I could give it a try... I might find a workaround...

-In the Voronoi Fracture, use a fixed connector (Voronoi Fracture > "Connectors" Tab > "Create Connector"). The default Force and Torque values are OK for your scene. 
 
-Switch the Dynamic Trigger to Immediately (Dynamics Body Tag > "Dynamics" Tab > "Trigger").
 
Attached the modified scene.
Voronoi Test Connector.c4d

Hi,
 
There's a Pose Morph Tag on your Mesh. It is in "Animate" Mode. It means that Cinema 4D will give priority to the poses from this tag (currently the "Default: Mesh" pose) and ignore your latest modifications.
 
To make modification of your character, switch to the Pose Morph "Edit" Mode and create a new Pose with the "Add Pose" button.
 
You could also delete the Pose Morph tag, if you don't need it during modeling....
 
 

You have to bake the simulation first to make it work with Volumes.
 
In the Dynamics Body Tag, "Cache" tab, click on "Bake Object".
 
(something else: place your Dynamics Body Tag on the Emitter not the Null)

In the Bitmap Shader attributes, you can change the Color Profile (Embedded, Linear, sRGB or Custom)
 
To access it, just click on the texture and go to the Shader Properties tab.

Yes,
 
You can use the "Position Track To Spline" command.
 
In the Timeline:
1.Select the camera
2. Then "Function" > "Position Track To Spline"

In your Object manager set up, the Displacer is deforming the low density Plane not the Subdivision Surface.  It explains the "low res" blurry result.
 
You have:
 
Subdivision Surface
>Plane
>>Displacer
 
While you should create the following hierarchy:
 
Subdivision Surface
>Plane
>Displacer
 
 
(As a guide line: a deformer will affect its direct parent)