The ISO setting was removed from the OctanRender plug-ins not too long ago.
The only way to reduce light power and still have the scene being bright is to compensate with the Exposure setting in the Render Settings.
Using the Hotpixel Removal node was already a good start to reduce the fireflies. It really only happens due to overpowered lights in your scene though.
The RED in the skin is when I use a very dark skin tone on a model,
That's because we tailored the skin shader to work with caucasian skin - you can easily fix this by increasing the "Scale" value in the "Medium" to a higher number - say 500-600 should do the trick for most dark skinned characters.
You would have to rotate the HDRi-map with the camera in order to achieve the effect in animation, that you're looking for.
You can do this by going into the environment tab of OctaneRender, then head to the Projection / Mesh Projection setting and in the drop-down box, set that to "Spherical Projection".
Now set the drop-down box below that to "3D Transformation"
This should give you new slider nodes to work with, and you want to look at the "Rotation Y" one for what you're looking for.
W10 64 bit | i7 3770K | MSI Geforce RTX 2080 (8GB) + GTX Titan Black (6GB) | 32 GB DDR3 RAM