Hi!
2nd Question: This is probably due to anti aliasing. Go into your Project Settings, search for Anti aliasing. If its is set to TemporalAA change it to MSAA. MSAA is usually the preferred AA method for VR, TemporalAA is applying to much for VR and its just gets blurry.
3rd Question: To have two different test setups you should have two separate pawns. In the World Outliner/World Settings you can set player pawn, have one for VR and one for monitor usage. Just swap out the player pawn and you should be good to go. This obviously requires the pawns to be set up correctly aswell!
Cheers!