what is houdini…I know i’ve heard of it but a quick google search comes up with nothing relevant.
But exported 3d cameras i have had some experiences with…
Sometimes the position gets wonky when importing in a camera. the starting point might not be 0,0.
Also sometimes the scale is wrong, maybe try adding a 3d null at 0,0 and attach the camera and everying else to it. sometimes scaling that null can fix problems because the import path is too small for ae to recognize..and then insert in your footage
Also i cant quite picture your setup but can you parent the footage to the camera.
Im not sure if this will help but I do have an expression that makes your footage always face your camera’s poi. it goes into the y rotation
delta = toWorld(anchorPoint) – thisComp.activeCamera.toWorld([0,0,0]);
radiansToDegrees(Math.atan2(delta[0],delta[2]))