Note that I do not work for RICOH. This is just my personal observation from helping to manage this independent forum, which is not a RICOH forum. (forum does receive sponsorship from RICOH) My understanding of how the camera works could be wrong. If you need more accurate information on the camera, please contact RICOH directly.
It’s possible that the multibracket shooting is only in the RICOH THETA app, not the other mobile apps that work with the camera and are from RICOH.
As far as I know, the HDR mode will not work for the purpose of using it as the light for VFX. I believe that people must create an EXR or HDRI file themselves, not with the SC2 camera. The image file created in HDR mode is a simple JPG file without the light information.
I am not familiar with using EXR files for VFX. I have seen people use the Z1 model. It has DNG/RAW mode. Maybe they are using that?
As far as I know, the output of the HDR mode of the camera is going to be a JPG file with the same characteristics of the JPG file of non-HDR. I believe that the purpose of the HDR mode of the camera is to simply show different light/dark in a picture. For example, to show the bright window and a dark corner of a room. This is for something like a real estate sales shot and as far as I know, is not for VFX lighting.
In the video I posted earlier, the author suggested that using a DSLR camera, likely on a rotating tripod would provide better lighting.
As I mentioned earlier, I don’t work for RICOH. This is an independent forum of people with the camera. So, my information could be wrong. Additionally, I don’t build VFX models, so I’m not familiar with the requirements. Though, I do appreciate you sharing your information on the requirements of VFX with the community.