> 185/75-14 is a smaller rolling diameter tire than the 185-14 tire
> usually recommended for Vanagons.

Yes

  Tire industry practice is to
> usually not list aspect ratio when it is 80; i.e., the recommended
> tire is 185/80-14.

Yes

  It is very common for North American tire dealers
> to ignore the difference and recommend 75-series tires>

Which should be ok if they recommend a 195/75R14, which is commonly listed
as an "alternative size" for the vanagon .