I'm not sure exactly what you're trying to do, but here are some references for tutorials on these types of rigs:
https://www.youtube.com/watch?v=6kmycdJjTkE
https://www.youtube.com/watch?v=5dNmL-NpU_w
https://www.youtube.com/watch?v=4sOTW4xYQvk
https://www.youtube.com/watch?v=jGCRKX5Zz5M

Unfortunately there are no tutorials yet.
I assume you want to avoid the intersection of the boxes when the spline curves.
The easiest solution for that is to add a Rigid Body Tag to the Cloner and set Follow Position and Rotation to 10. That way the Simulation will make sure the boxes don't overlap while the movement is followed.
https://www.dropbox.com/scl/fi/j81wbkvo2zz4dj6pio6es/spline-distribution_0001-RBD.c4d?rlkey=e30cpnm2cczlvww4wj3677djs&dl=0

This has been fixed in the latest C4D hotfix 2026.3.3

The Lighting and shading information will not appear in the Alpha channel.
Why don't you just use the Beauty pass in after effects as a Matte?

To do that better, first emit the particles facing the camera by using "Alignment-> forward Vector "Target" and drag the camera.
Then just set the Follow Rotation to 100.

https://www.dropbox.com/scl/fi/p32613ars2ml9iy7a0fgj/emit-RBD-facing-Camera-01A.c4d?rlkey=9x2sckuslfc5sbierupn51p3j&dl=0

without some sort of project file it's impossible to know what's going on... can you please simplify the project and send a link?

if something seems broken, the best way is to contact customer support.

you only want to colorize this or mix the red GI with whatever your pillar color will be?

@Dutchbird
This is something you should bring up with tech support...

unfortunately not without some script or something...