I just put my leap experiment up on if you want to have a look. https://.com/opamp77/UnrealEngine/tree/4.10Experiments
Unfortunalty after thurther testing this does’nt appear to totally remove the rotational latency only reduce it but maybe im doing something wrong.
As far as the Orion branch is concerned I noticed a few merges into the Master/4.11 branch after looking at a few more of them It appears that Orion is Epics internal name for Paragon.
Looking ahead it looks like an applylateupdate() function is now being called within the hmd plugins.
https://.com/EpicGames/UnrealEngine/search?utf8=%E2%9C%93&q=ApplyLateUpdate
It looks like in 4.11 you can inform the HeadmountedDisplay module of components that you would like updating on the render thread.
https://.com/EpicGames/UnrealEngine/search?utf8=%E2%9C%93&q=setuplateupdate
And it look like the camera gets a late update by default.
If im right this should make things a bit easier.