Yes the reflector shape will alter the light output/pattern some. How much I can't say. But fog's aren't really meant for anything these days other than appearance.
The little rubber hose is a moisture vent. That way if water gets inside it has a path to evaporate out ... or, it has a path to enter the lights.
Don't "think outside the box".
There is no box.
Do it correct, or do it twice.