Hopefully this is the real fix for now:
https://github.com/EpicGames/UnrealEngine/commit/96fbb8d0f247ef390c46e64c1d1e5d6b34857ca2
The issue is that we are still on Steamworks 1.32 which still has the old SteamVR API exposed. So for any potentially shared export functions, I use GetProcAddress to explicitly grab the function pointer from the correct DLL.
And yes, there is a way to set HMD plugin precedence, at least in 4.8. Please see BaseEngine.ini in 4.8p3+:
[HMDPluginPriority]
; Since SteamVR also works with the Oculus Rift, give priority to the native Oculus plugin before trying SteamVR
OculusRift=20
SteamVR=10