Let me be more clear, by unwrapped I mean taking the equirectangular image and using the lens tool in mocha to isolate an unwarped NON-equirectangualr view. Precomp that view. Apply mocha VR, and in the lens tab make sure you have set the lens to “none.” Now you can solve for that section of your footage. Solve for your camera using two non-coplanar planes and export your camera to your comp. Add your 3D objects in AE. Precomp that again. Re-warp it using the mocha lens tool.
The 3D solver does not work in equirectangular lens mode. But it is available in Mocha VR if you turn the lens warp off. Same thing for stabilize, it doesn’t work in equirectangular mode. To stabilize VR footage you need to use the “reorient” module in mocha VR.