Great progress with the renders!
The second render is much smoother, but feels too dark. I really liked the light levels of the original render.
Composition-wise, consider offsetting the camera so as to move the red plant pot away from the very center of the image.
Wonderful work on the carpet!

Fantastic abstract images!
I like the sense of movement and the striking color scheme.
It's nice to see variety like this with the use of octane.

Cool stuff.
I particularly like "proba4.png" with the depth of field and lens flare.
It would be great to see an animated fly-through of the city!

This looks great!

It would definitely be nice to see a smoother render! Have you tried rendering out a larger size image and then downscaling it?
Also the back wall is a little too bright and is eating up the chair detail. Maybe try lowering the turbidity if you're using daylight system.
Nice work!