YES YES YES. Finally solved it -> BP hands now working on Oculus Quest. Its to do with UE4 4.20 and some android bug:
See Forum post of possible solutions: https://answers.unrealengine.com/questions/848288/skeletal-mesh-is-not-visible-in-mobile-preview-aft.html
I first changed UE4 rendering to ES2 Preview (Some say 3.1 will solve all skeletal mesh problems).
Configured LowPolyHand as shown in image.
Apparently in HandBP on Even BeginPlay, if on Android LowPolyHand is used.
Make sure as well in HandBP skeletal component properties mesh is visible or not hidden in game.