Definitely a lot of warnings are annoying.
Well the one I mentioned is the only integer Switch, and having a WallVariant value that isn’t on the switch is the only reason I can see for getting that warning. 
So double check them. And check if they are actually the same warning.
The way I’d prevent it entirely would probably be to have it check if the integer is a valid value (between 0 and 3) before the switch. But that really shouldn’t be necessary since we don’t want to use wrong values.
If it still gives a warning you could check if it still does without level streaming? Can’t imagine that making any difference though.
An alternative would be to convert them to meshes: Actor → Merge