Insert "flat" 4K video into VR video

I'm ending a VR program in which I want to insert traditional flat 4K video to help tell a specific part of the story with out distorting it. 

I also want to from time to time go to the flattened equirectangular 360º shot for a super wide establishing shot.

I'm sure that I was able to get the big flattened WS before I installed the Skybox plugins, but I sure haven't figured out how to do it now.

Thanks for any and all wisdom.

Jim