Switchable VR cardboard output under iOS ?

My client wants an App out of exhibition-stereo-360-panoramas enriched with info-points.
Under iOS cardboard.
And you should be able to switch the stereo/vcardboard output on/off by a switch inside the app.
I’ve done a few Vive anf GearVR apps so far, so my experience is medium. We made a few iOS apps with other authoring systems, but not VR.
How do I create this in Unreal?
Is there a possibility to switch cardboard output to mono?
Or the other way around: program everything from ground up with accelerometer inputs instead of Cardboard-input plus self made stereo output? How?
Does Unreal under iOS allow this?
What would be the starting point for this madness?

I’m also curious to learn if there’s a starting guide for deploying on iOS cardboard using the latest engine version.