There were a couple of threads few days ago around a connected topic. Here the reference: Shifting Image to Different locations. - VR and AR Development - Unreal Engine Forums
A potential solution revolves around using stereoscopic materials to separately address the projection of each eye. Now not sure whether that could be helpful in your case.
CalculateStereoViewOffset refers to a vision model where the eyes look both in the same direction. If you have someone cross-eyed, you will have to change the direction one of the eye looks to, hence with a different projection. I think this would be anyway tricky to their brain since it is used to compensate for cross-vision and now you are simulating a “normal” condition. Not sure what the reaction would be (including potential simulation sickness).
Anyway, you can try to look into the code for Instanced Stereo Rendering, that’s where some of the VR “magic” happens when this mode is active and where the two instances, one for each eye, are created.
Very interesting project though. Would love to learn more about it. Let’s stay in touch. 
Cheers,
Marco.