advancing with the exercise for lighting fundamentals: Getting ever slighty closer:

To fix:
still those vertical rays, now I tried with cones that have a colorramp for opacity layer to fake flares with a slight emission. Doesn’t look natural.
Color of the blue should be more purple
The glare is too much on the face, yet nice on the projection light, not sure if this can be fixed with a color ramp and transparancy node in compositing. To check.
add some smokey texture to the light.

The last one is getting closer, even though the rays are too fake (they are 🙂 ) and the smoke is a bit too dirty (texture was not high of quality.) I’m getting to image 2. Any feedback from you guys would be welcome before I can submit. cheers!
I woke up this morning with the simplest insight ever… instead of working on creating light beams, I should have created shadows…! to fix my issue with those light beams, I now created a point light emitting the same light as the projector light and I created an invisible cone with holes in to cast shadows. I kep big holes so the “light beams ” are broad, but as the holes get smaller, you get more beams like on the original, have a look, pretty happy with the final result!: